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Han MJ, Luo C, Hu H, Lin M, Lu K, Shen J, Ren J, Ye Y, Westhof E, Tong X, Dai F. Multiple independent origins of the female W chromosome in moths and butterflies. SCIENCE ADVANCES 2024; 10:eadm9851. [PMID: 38896616 PMCID: PMC11186504 DOI: 10.1126/sciadv.adm9851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 05/14/2024] [Indexed: 06/21/2024]
Abstract
Lepidoptera, the most diverse group of insects, exhibit female heterogamy (Z0 or ZW), which is different from most other insects (male heterogamy, XY). Previous studies suggest a single origin of the Z chromosome. However, the origin of the lepidopteran W chromosome remains poorly understood. Here, we assemble the genome from females down to the chromosome level of a model insect (Bombyx mori) and identify a W chromosome of approximately 10.1 megabase using a newly developed tool. In addition, we identify 3593 genes that were not previously annotated in the genomes of B. mori. Comparisons of 21 lepidopteran species (including 17 ZW and four Z0 systems) and three trichopteran species (Z0 system) reveal that the formation of Ditrysia W involves multiple mechanisms, including previously proposed canonical and noncanonical models, as well as a newly proposed mechanism called single-Z turnover. We conclude that there are multiple independent origins of the W chromosome in the Ditrysia (most moths and all butterflies) of Lepidoptera.
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Affiliation(s)
- Min-Jin Han
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Chaorui Luo
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
| | - Hai Hu
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Meixing Lin
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
| | - Kunpeng Lu
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
| | - Jianghong Shen
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
| | - Jianyu Ren
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
| | - Yanzhuo Ye
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
| | - Eric Westhof
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
- Architecture et Réactivité de l’ARN, Institut de Biologie Moléculaire et Cellulaire, UPR9002 CNRS, Université de Strasbourg, Strasbourg 67084, France
| | - Xiaoling Tong
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Fangyin Dai
- State Key Laboratory of Resource Insects, Institute of Sericulture and Systems Biology, Southwest University, Chongqing 400715, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
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Fukui T, Shoji K, Kiuchi T, Suzuki Y, Katsuma S. Masculinizer is not post-transcriptionally regulated by female-specific piRNAs during sex determination in the Asian corn borer, Ostrinia furnacalis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 156:103946. [PMID: 37075905 DOI: 10.1016/j.ibmb.2023.103946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/31/2023] [Accepted: 04/16/2023] [Indexed: 05/03/2023]
Abstract
Lepidopteran insects are heterogametic in females, although most insect species are heterogametic in males. In a lepidopteran model species, the silkworm Bombyx mori (Bombycoidea), the uppermost sex determinant Feminizer (Fem) has been identified on the female-specific W chromosome. Fem is a precursor of PIWI-interacting small RNA (piRNA). Fem piRNA forms a complex with Siwi, one of the two B. mori PIWI-clade Argonaute proteins. In female embryos, Fem piRNA-Siwi complex cleaves the mRNA of the male-determining gene Masculinizer (Masc), directing the female-determining pathway. In male embryos, Masc activates the male-determining pathway in the absence of Fem piRNA. Recently, W chromosome-derived piRNAs complementary to Masc mRNA have also been identified in the diamondback moth Plutella xylostella (Yponomeutoidea), indicating the convergent evolution of piRNA-dependent sex determination in Lepidoptera. Here, we show that this is not the case in the Asian corn borer, Ostrinia furnacalis (Pyraloidea). Although our previous studies demonstrated that O. furnacalis Masc (OfMasc) has a masculinizing function in the embryonic stage, the expression level of OfMasc was indistinguishable between the sexes at the timing of sex determination. Deep sequencing analysis identified no female-specific small RNAs mapped onto OfMasc mRNA. Embryonic knockdown of two PIWI genes did not affect the expression level of OfMasc in either sex. These results demonstrated that piRNA-dependent reduction of Masc mRNA in female embryos is not a common strategy of sex determination, which suggests the possibility of divergent evolution of sex determinants across the order Lepidoptera.
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Affiliation(s)
- Takahiro Fukui
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Keisuke Shoji
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Yutaka Suzuki
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8581, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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Chen K, Yang X, Yang D, Huang Y. Spindle-E is essential for gametogenesis in the silkworm, Bombyx mori. INSECT SCIENCE 2023; 30:293-304. [PMID: 35866721 DOI: 10.1111/1744-7917.13096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 06/06/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
As a defense mechanism against transposable elements, the PIWI-interacting RNA (piRNA) pathway maintains genomic integrity and ensures proper gametogenesis in gonads. Numerous factors are orchestrated to ensure normal operation of the piRNA pathway. Spindle-E (Spn-E) gene was one of the first genes shown to participate in the piRNA pathway. In this study, we performed functional analysis of Spn-E in the model lepidopteran insect, Bombyx mori. Unlike the germline-specific expression pattern observed in Drosophila and mouse, BmSpn-E was ubiquitously expressed in all tissues tested, and it was highly expressed in gonads. Immunofluorescent staining showed that BmSpn-E was localized in both germ cells and somatic cells in ovary and was expressed in spermatocytes in testis. We used a binary transgenic CRISPR/Cas9 system to construct BmSpn-E mutants. Loss of BmSpn-E expression caused derepression of transposons in gonads. We also found that mutant gonads were much smaller than wild-type gonads and that the number of germ cells was considerably lower in mutant gonads. Quantitative real-time PCR analysis and TUNEL staining revealed that apoptosis was greatly enhanced in mutant gonads. Further, we found that the BmSpn-E mutation impacted gonadal development and gametogenesis at the early larval stage. In summary, our data provided the first evidence that BmSpn-E plays vital roles in gonadal development and gametogenesis in B. mori.
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Affiliation(s)
- Kai Chen
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu Province, China
| | - Xu Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
| | - Dehong Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, China
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Santos D, Feng M, Kolliopoulou A, Taning CNT, Sun J, Swevers L. What Are the Functional Roles of Piwi Proteins and piRNAs in Insects? INSECTS 2023; 14:insects14020187. [PMID: 36835756 PMCID: PMC9962485 DOI: 10.3390/insects14020187] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/09/2023] [Accepted: 02/11/2023] [Indexed: 06/01/2023]
Abstract
Research on Piwi proteins and piRNAs in insects has focused on three experimental models: oogenesis and spermatogenesis in Drosophila melanogaster, the antiviral response in Aedes mosquitoes and the molecular analysis of primary and secondary piRNA biogenesis in Bombyx mori-derived BmN4 cells. Significant unique and complementary information has been acquired and has led to a greater appreciation of the complexity of piRNA biogenesis and Piwi protein function. Studies performed in other insect species are emerging and promise to add to the current state of the art on the roles of piRNAs and Piwi proteins. Although the primary role of the piRNA pathway is genome defense against transposons, particularly in the germline, recent findings also indicate an expansion of its functions. In this review, an extensive overview is presented of the knowledge of the piRNA pathway that so far has accumulated in insects. Following a presentation of the three major models, data from other insects were also discussed. Finally, the mechanisms for the expansion of the function of the piRNA pathway from transposon control to gene regulation were considered.
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Affiliation(s)
- Dulce Santos
- Research Group of Molecular Developmental Physiology and Signal Transduction, Division of Animal Physiology and Neurobiology, Department of Biology, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium
| | - Min Feng
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Anna Kolliopoulou
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Aghia Paraskevi, 15341 Athens, Greece
| | - Clauvis N. T. Taning
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - Jingchen Sun
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences & Applications, National Centre for Scientific Research “Demokritos”, Aghia Paraskevi, 15341 Athens, Greece
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Oliveira JIN, Cardoso AL, Wolf IR, de Oliveira RA, Martins C. First characterization of PIWI-interacting RNA clusters in a cichlid fish with a B chromosome. BMC Biol 2022; 20:204. [PMID: 36127679 PMCID: PMC9490952 DOI: 10.1186/s12915-022-01403-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 09/06/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND B chromosomes are extra elements found in several eukaryote species. Usually, they do not express a phenotype in the host. However, advances in bioinformatics over the last decades have allowed us to describe several genes and molecular functions related to B chromosomes. These advances enable investigations of the relationship between the B chromosome and the host to understand how this element has been preserved in genomes. However, considering that transposable elements (TEs) are highly abundant in this supernumerary chromosome, there is a lack of knowledge concerning the dynamics of TE control in B-carrying cells. Thus, the present study characterized PIWI-interacting RNA (piRNA) clusters and pathways responsible for silencing the mobilization of TEs in gonads of the cichlid fish Astatotilapia latifasciata carrying the B chromosome. RESULTS Through small RNA-seq and genome assembly, we predicted and annotated piRNA clusters in the A. latifasciata genome for the first time. We observed that these clusters had biased expression related to sex and the presence of the B chromosome. Furthermore, three piRNA clusters, named curupira, were identified in the B chromosome. Two of them were expressed exclusively in gonads of samples with the B chromosome. The composition of these curupira sequences was derived from LTR, LINE, and DNA elements, representing old and recent transposition events in the A. latifasciata genome and the B chromosome. The presence of the B chromosome also affected the expression of piRNA pathway genes. The mitochondrial cardiolipin hydrolase-like (pld6) gene is present in the B chromosome, as previously reported, and an increase in its expression was detected in gonads with the B chromosome. CONCLUSIONS Due to the high abundance of TEs in the B chromosome, it was possible to investigate the origin of piRNA from these jumping genes. We hypothesize that the B chromosome has evolved its own genomic guardians to prevent uncontrolled TE mobilization. Furthermore, we also detected an expression bias in the presence of the B chromosome over A. latifasciata piRNA clusters and pathway genes.
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Affiliation(s)
- Jordana Inácio Nascimento Oliveira
- Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu, SP, 18618-689, Brazil
| | - Adauto Lima Cardoso
- Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu, SP, 18618-689, Brazil
| | - Ivan Rodrigo Wolf
- Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu, SP, 18618-689, Brazil
| | - Rogério Antônio de Oliveira
- Department of Biostatistics, Plant Biology, Parasitology and Zoology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Cesar Martins
- Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu, SP, 18618-689, Brazil.
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Kawamoto M, Kiuchi T, Katsuma S. SilkBase: an integrated transcriptomic and genomic database for Bombyx mori and related species. Database (Oxford) 2022; 2022:6603636. [PMID: 35670730 PMCID: PMC9216573 DOI: 10.1093/database/baac040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/21/2022] [Accepted: 05/21/2022] [Indexed: 11/13/2022]
Abstract
We introduce SilkBase as an integrated database for transcriptomic and genomic resources of the domesticated silkworm Bombyx mori and related species. SilkBase is the oldest B. mori database that was originally established as the expressed sequence tag database since 1999. Here, we upgraded the database by including the datasets of the newly assembled B. mori complete genome sequence, predicted gene models, bacterial artificial chromosome (BAC)-end and fosmid-end sequences, complementary DNA (cDNA) reads from 69 libraries, RNA-seq data from 10 libraries, PIWI-interacting RNAs (piRNAs) from 13 libraries, ChIP-seq data of 9 histone modifications and HP1 proteins and transcriptome and/or genome data of four B. mori-related species, i.e. Bombyx mandarina, Trilocha varians, Ernolatia moorei and Samia ricini. Our new integrated genome browser easily provides a snapshot of tissue- and stage-specific gene expression, alternative splicing, production of piRNAs and histone modifications at the gene locus of interest. Moreover, SilkBase is useful for performing comparative studies among five closely related lepidopteran insects. Database URL: https://silkbase.ab.a.u-tokyo.ac.jp
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Affiliation(s)
- Munetaka Kawamoto
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.,Infinity Matrix, Shiohama, Koto-ku, Tokyo 135-0043, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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Warmuth VM, Weissensteiner MH, Wolf J. Ineffective silencing of transposable elements on an avian W Chromosome. Genome Res 2022; 32:671-681. [PMID: 35149543 PMCID: PMC8997356 DOI: 10.1101/gr.275465.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 02/08/2022] [Indexed: 11/24/2022]
Abstract
One of the defining features of transposable elements (TEs) is their ability to move to new locations in the host genome. To minimise the potentially deleterious effects of de novo TE insertions, hosts have evolved several mechanisms to control TE activity, including recombination-mediated removal and epigenetic silencing; however, increasing evidence suggests that silencing of TEs is often incomplete. The crow family experienced a recent radiation of LTR retrotransposons (LTRs), offering an opportunity to gain insight into the regulatory control of young, potentially still active TEs. We quantified the abundance of TE-derived transcripts across several tissues in 15 Eurasian crows (Corvus (corone) spp.) raised under common garden conditions and find evidence for ineffective TE suppression on the female-specific W Chromosome. Using RNA-seq data, we show that ~ 9.5% of all transcribed TEs had considerably greater (average: 16-fold) transcript abundance in female crows, and that more than 85% of these female-biased TEs originated on the W Chromosome. After accounting for differences in TE density among chromosomal classes, W-linked TEs were significantly more highly expressed than TEs residing on other chromosomes, consistent with ineffective silencing on the former. Together, our results suggest that the crow W Chromosome acts as a source of transcriptionally active TEs, with possible negative fitness consequences for female birds analogous to Drosophila (an X/Y system), where overexpression of Y-linked TEs is associated with male-specific aging and fitness loss ('toxic Y').
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Maier MC, McInerney MRA, Graves JAM, Charchar FJ. Noncoding Genes on Sex Chromosomes and Their Function in Sex Determination, Dosage Compensation, Male Traits, and Diseases. Sex Dev 2021; 15:432-440. [PMID: 34794153 DOI: 10.1159/000519622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/13/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian Y chromosome has evolved in many species into a specialized chromosome that contributes to sex development among other male phenotypes. This function is well studied in terms of protein-coding genes. Less is known about the noncoding genome on the Y chromosome and its contribution to both sex development and other traits. Once considered junk genetic material, noncoding RNAs are now known to contribute to the regulation of gene expression and to play an important role in refining cellular functions. The prime examples are noncoding genes on the X chromosome, which mitigate the differential dosage of genes on sex chromosomes. Here, we discuss the evolution of noncoding RNAs on the Y chromosome and the emerging evidence of how micro, long, and circular noncoding RNAs transcribed from the Y chromosome contribute to sex differentiation. We briefly touch on emerging evidence that these noncoding RNAs also contribute to some other important clinical phenotypes in humans.
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Affiliation(s)
- Michelle C Maier
- Health Innovation & Transformation Centre, Federation University, Mt Helen, Victoria, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, Victoria, Australia
| | - Molly-Rose A McInerney
- Health Innovation & Transformation Centre, Federation University, Mt Helen, Victoria, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, Victoria, Australia
| | | | - Fadi J Charchar
- Health Innovation & Transformation Centre, Federation University, Mt Helen, Victoria, Australia.,Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
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Yang F, Zhang Z, Hu B, Yu Y, Tan A. A CCCH zinc finger gene regulates doublesex alternative splicing and male development in Bombyx mori. INSECT SCIENCE 2021; 28:1253-1261. [PMID: 33029871 DOI: 10.1111/1744-7917.12876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/26/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Recent identification of a Piwi-interacting RNA (piRNA)-initiated sex determination cascade in the silkworm, Bombyx mori, provides novel insights into high diversity of insect sex determination pathways. In this system, the W-chromosome-derived Fem piRNA is the primary sex determination signal. A CCCH-type zinc finger gene Masculinizer (Masc), which is targeted by Fem piRNA-PIWI complex in female animals, is indispensable for male-specific splicing of B. mori doublesex (Bmdsx). Although many genes involved in this cascade have been identified, the regulatory mechanisms of silkworm sex determination remain to be elucidated. Here we show that another CCCH-type zinc finger gene, Bmznf-2, is a masculinization factor in B. mori. Bmznf-2 shows testis-abundant expression and loss of Bmznf-2 function via clustered regularly interspaced short palindromic repeats / single-guide RNA-mediated mutagenesis results in feminized differentiation and appearance of the female-specific splicing variants of Bmdsx transcripts in males. In contrast, there is no phenotypic consequence in mutant females. In mutant males, relative messenger RNA expression levels of female-dominant genes such as vitellogenin and sex-specific storage protein 1 are significantly elevated while several male-dominant genes are significantly down-regulated. Furthermore, male mutants show delayed developmental timing, smaller body sizes of larvae and malformation of moth wings. Our data thus reveal that Bmznf-2 plays an indispensable role in silkworm male sexual differentiation.
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Affiliation(s)
- Fangying Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhongjie Zhang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bo Hu
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ye Yu
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Anjiang Tan
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
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Kiuchi T, Katsuma S. Functional Characterization of Silkworm PIWI Proteins by Embryonic RNAi. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2360:19-31. [PMID: 34495504 DOI: 10.1007/978-1-0716-1633-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
The molecular mechanisms of sex-determination systems among insect orders and species are diverse. Therefore, genes involved in sex determination are strong candidates for insect pest management. Even though lepidopterans are major agricultural insect pests that cause widespread economic damage to various crops, their sex-determination systems have not been fully elucidated, even in the silkworm (Bombyx mori), a model lepidopteran insect. In 2014, we found that a female-specific W chromosome-derived PIWI-interacting RNA (piRNA) determines femaleness in silkworms. To analyze the function of two core silkworm piRNA biogenesis pathway genes, Siwi and BmAgo3, in the sex-determination system, we developed a genomic DNA and total RNA extraction strategy for a siRNA-injected single embryo. The siRNA-injected embryo can be molecularly sexed by W chromosome-specific DNA markers. Using complementary DNA (cDNA) reverse transcribed from the sexed RNA, we evaluated the knockdown effect of the PIWI protein-coding genes on a sexual development-related gene, Bombyx mori doublesex.
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Affiliation(s)
- Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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11
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Identification and Characterization of the Masculinizing Function of the Helicoverpa armigera Masc Gene. Int J Mol Sci 2021; 22:ijms22168650. [PMID: 34445352 PMCID: PMC8395511 DOI: 10.3390/ijms22168650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022] Open
Abstract
The Masculinizer (Masc) gene has been known to control sex development and dosage compensation in lepidopterans. However, it remains unclear whether its ortholog exists and plays the same roles in distantly related lepidopterans such as Helicoverpa armigera. To address this question, we cloned Masc from H. armigera (HaMasc), which contains all essential functional domains of BmMasc, albeit with less than 30% amino acid sequence identity with BmMasc. Genomic PCR and qPCR analyses showed that HaMasc is a Z chromosome-linked gene since its genomic content in males (ZZ) was two times greater than that in females (ZW). RT-PCR and RT-qPCR analyses revealed that HaMasc expression was sex- and stage-biased, with significantly more transcripts in males and eggs than in females and other stages. Transfection of a mixture of three siRNAs of HaMasc into a male embryonic cell line of H. armigera led to the appearance of female-specific mRNA splicing isoforms of H. armigeradoublesex (Hadsx), a downstream target gene of HaMasc in the H. armigera sex determination pathway. The knockdown of HaMasc, starting from the third instar larvae resulted in a shift of Hadsx splicing from male to female isoforms, smaller male pupa and testes, fewer but larger/longer spermatocytes and sperm bundles, delayed pupation and internal fusion of the testes and follicles. These data demonstrate that HaMasc functions as a masculinizing gene in the H. armigera sex-determination cascade.
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Yang X, Chen K, Wang Y, Yang D, Huang Y. The Sex Determination Cascade in the Silkworm. Genes (Basel) 2021; 12:genes12020315. [PMID: 33672402 PMCID: PMC7926724 DOI: 10.3390/genes12020315] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 12/22/2022] Open
Abstract
In insects, sex determination pathways involve three levels of master regulators: primary signals, which determine the sex; executors, which control sex-specific differentiation of tissues and organs; and transducers, which link the primary signals to the executors. The primary signals differ widely among insect species. In Diptera alone, several unrelated primary sex determiners have been identified. However, the doublesex (dsx) gene is highly conserved as the executor component across multiple insect orders. The transducer level shows an intermediate level of conservation. In many, but not all examined insects, a key transducer role is performed by transformer (tra), which controls sex-specific splicing of dsx. In Lepidoptera, studies of sex determination have focused on the lepidopteran model species Bombyx mori (the silkworm). In B. mori, the primary signal of sex determination cascade starts from Fem, a female-specific PIWI-interacting RNA, and its targeting gene Masc, which is apparently specific to and conserved among Lepidoptera. Tra has not been found in Lepidoptera. Instead, the B. mori PSI protein binds directly to dsx pre-mRNA and regulates its alternative splicing to produce male- and female-specific transcripts. Despite this basic understanding of the molecular mechanisms underlying sex determination, the links among the primary signals, transducers and executors remain largely unknown in Lepidoptera. In this review, we focus on the latest findings regarding the functions and working mechanisms of genes involved in feminization and masculinization in Lepidoptera and discuss directions for future research of sex determination in the silkworm.
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Affiliation(s)
- Xu Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; (X.Y.); (K.C.); (Y.W.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; (X.Y.); (K.C.); (Y.W.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaohui Wang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; (X.Y.); (K.C.); (Y.W.); (D.Y.)
| | - Dehong Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; (X.Y.); (K.C.); (Y.W.); (D.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; (X.Y.); (K.C.); (Y.W.); (D.Y.)
- Correspondence:
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13
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Chen K, Yu Y, Yang D, Yang X, Tang L, Liu Y, Luo X, R. Walter J, Liu Z, Xu J, Huang Y. Gtsf1 is essential for proper female sex determination and transposon silencing in the silkworm, Bombyx mori. PLoS Genet 2020; 16:e1009194. [PMID: 33137136 PMCID: PMC7660909 DOI: 10.1371/journal.pgen.1009194] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 11/12/2020] [Accepted: 10/14/2020] [Indexed: 01/15/2023] Open
Abstract
Sex determination pathways are astoundingly diverse in insects. For instance, the silk moth Bombyx mori uniquely use various components of the piRNA pathway to produce the Fem signal for specification of the female fate. In this study, we identified BmGTSF1 as a novel piRNA factor which participates in B. mori sex determination. We found that BmGtsf1 has a distinct expression pattern compared to Drosophila and mouse. CRISPR/Cas9 induced mutation in BmGtsf1 resulted in partial sex reversal in genotypically female animals by shifting expression of the downstream targets BmMasc and Bmdsx to the male pattern. As levels of Fem piRNAs were substantially reduced in female mutants, we concluded that BmGtsf1 plays a critical role in the biogenesis of the feminizing signal. We also demonstrated that BmGTSF1 physically interacted with BmSIWI, a protein previously reported to be involved in female sex determination, indicating BmGTSF1 function as the cofactor of BmSIWI. BmGtsf1 mutation resulted in piRNA pathway dysregulation, including piRNA biogenesis defects and transposon derepression, suggesting BmGtsf1 is also a piRNA factor in the silkworm. Furthermore, we found that BmGtsf1 mutation leads to gametogenesis defects in both male and female. Our data suggested that BmGtsf1 is a new component involved in the sex determination pathway in B. mori. Sex determination is a fundamentally important process in most sexually reproducing metazoan. Nevertheless, the underlying mechanisms of sex determination are highly diverse. In B. mori, piRNAs derived from the W-chromosome-linked Fem precursor serve as the primary female determining signal. However, we still know little about the initiation of B. mori sex determination and its relationship with piRNA pathway. Here, we provided evidence that BmGTSF1 is a novel piRNA factor which is indispensable for B.mori female sex determination. Mutations in BmGtsf1 resulted in dysregulation of the piRNA pathway and caused partial female-male sex reversal. We also detected dramatic diminution of Fem piRNA in female mutant, indicating BmGTSF1 regulates B. mori sex determination via piRNA pathway. More importantly, we showed that BmGTSF1 interacted with BmSIWI, which protein had been reported to be involved in piRNA pathway and sex determination in B. mori, supporting the conclusion that BmGTSF1 is a novel factor for piRNA pathway and sex determination.
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Affiliation(s)
- Kai Chen
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Ye Yu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Dehong Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xu Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Linmeng Tang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Yujia Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xingyu Luo
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - James R. Walter
- Department of Ecology and Evolutionary Biology, University of Kansas, NV, United States of America
| | - Zulian Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jun Xu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (JX); (YH)
| | - Yongping Huang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
- * E-mail: (JX); (YH)
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Aguirre C, Olivares N, Hinrichsen P. An Efficient Duplex PCR Method for Sex Identification of the European Grapevine Moth Lobesia botrana (Lepidoptera: Tortricidae) at Any Developmental Stage. JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:2505-2510. [PMID: 32676656 DOI: 10.1093/jee/toaa155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Indexed: 06/11/2023]
Abstract
Many genetic studies in insects require sex identification of individuals in all developmental stages. The most common sex chromosome system in lepidopterans is WZ/ZZ; the W chromosome is present only in females. Based on two W chromosome-specific short sequences (CpW2 and CpW5) described in Cydia pomonella (L.) (Lepidoptera: Tortricidae), we identified homologous female-specific sequences in Lobesia botrana Den. & Schiff, a polyphagous and very harmful species present in Chile since 2008. From this starting point, we extended the sequence information using the inverse PCR method, identifying the first W-specific sequences described up to now for the moth. Finally, we developed a duplex PCR method for rapid and sensitive determination of sex in L. botrana from larva to adult. The method showed a detection limit of 1 pg of genomic DNA; a blind panel of samples exhibited exact correspondence with the morphological identification. These results will be very useful for studies requiring sex-specific analyses at any developmental stage, contributing also to the understanding of gene expression in the insect, as well as to the eventual development of control protocols against the moth, such as the development of genetic sexing strains for the implementation of the sterile insect technique.
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Affiliation(s)
- Carlos Aguirre
- Instituto de Investigaciones Agropecuarias, INIA-La Platina, Santiago, Chile
| | - Natalia Olivares
- Instituto de Investigaciones Agropecuarias, INIA-La Cruz, La Cruz, Quillota, Chile
| | - Patricio Hinrichsen
- Instituto de Investigaciones Agropecuarias, INIA-La Platina, Santiago, Chile
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15
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Wang Y, Li J, Wan QX, Zhao Q, Wang KX, Zha XF. Spliceosomal Protein Gene BmSPX Regulates Reproductive Organ Development in Bombyx mori. Int J Mol Sci 2020; 21:ijms21072579. [PMID: 32276369 PMCID: PMC7177926 DOI: 10.3390/ijms21072579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/03/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023] Open
Abstract
Sex determination and differentiation are nearly universal to all eukaryotic organisms, encompassing diverse systems and mechanisms. Here, we identified a spliceosomal protein gene BmSPX involved in sex determination of the lepidopeteran insect, Bombyx mori. In a transgenic silkworm line that overexpressed the BmSPX gene, transgenic silkworm males exhibited differences in their external genitalia compared to wild-type males, but normal internal genitalia. Additionally, transgenic silkworm females exhibited a developmental disorder of the reproductive organs. Upregulation of BmSPX significantly increased the expression levels of sex-determining genes (BmMasc and BmIMP) and reduced the female-type splice isoform of Bmdsx, which is a key switch gene downstream of the sex-determination pathway. Additionally, co-immunoprecipitation assays confirmed an interaction between the BmSPX protein and BmPSI, an upstream regulatory factor of Bmdsx. Quantitative real-time PCR showed that BmSPX over-expression upregulated the expression of the Hox gene abdominal-B (Adb-B), which is required for specification of the posterior abdomen, external genitalia, and gonads of insects, as well as the genes in the Receptor Tyrosine Kinase (RTK) signaling pathway. In conclusion, our study suggested the involvement of BmSPX, identified as a novel regulatory factor, in the sex-determination pathway and regulation of reproductive organ development in silkworms.
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Affiliation(s)
- Yao Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; (Y.W.); (J.L.); (Q.-X.W.); (Q.Z.); (K.-X.W.)
- Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
- Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China
- The State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Science, Fudan University, Shanghai 200438, China
| | - Juan Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; (Y.W.); (J.L.); (Q.-X.W.); (Q.Z.); (K.-X.W.)
| | - Qiu-Xing Wan
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; (Y.W.); (J.L.); (Q.-X.W.); (Q.Z.); (K.-X.W.)
| | - Qin Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; (Y.W.); (J.L.); (Q.-X.W.); (Q.Z.); (K.-X.W.)
| | - Kai-Xuan Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; (Y.W.); (J.L.); (Q.-X.W.); (Q.Z.); (K.-X.W.)
| | - Xing-Fu Zha
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; (Y.W.); (J.L.); (Q.-X.W.); (Q.Z.); (K.-X.W.)
- Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China
- Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China
- Correspondence: ; Tel.: +86-23-68251573; Fax: +86-23-68251128
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miRNA-1-3p is an early embryonic male sex-determining factor in the Oriental fruit fly Bactrocera dorsalis. Nat Commun 2020; 11:932. [PMID: 32071305 PMCID: PMC7029022 DOI: 10.1038/s41467-020-14622-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 07/18/2019] [Indexed: 11/08/2022] Open
Abstract
Regulation of male sexual differentiation by a Y chromosome-linked male determining factor (M-factor) is one of a diverse array of sex determination mechanisms found in insects. By deep sequencing of small RNAs from Bactrocera dorsalis early embryos, we identified an autosomal-derived microRNA, miR-1-3p, that has predicted target sites in the transformer gene (Bdtra) required for female sex determination. We further demonstrate by both in vitro and in vivo tests that miR-1-3p suppresses Bdtra expression. Injection of a miR-1-3p mimic in early embryos results in 87-92% phenotypic males, whereas knockdown of miR-1-3p by an inhibitor results in 67-77% phenotypic females. Finally, CRISPR/Cas9-mediated knockout of miR-1-3p results in the expression of female-specific splice variants of Bdtra and doublesex (Bddsx), and induced sex reversal of XY individuals into phenotypic females. These results indicate that miR-1-3p is required for male sex determination in early embryogenesis in B. dorsalis as an intermediate male determiner.
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17
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Activity and inactivity of moth sex chromosomes in somatic and meiotic cells. Chromosoma 2019; 128:533-545. [PMID: 31410566 DOI: 10.1007/s00412-019-00722-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/17/2019] [Accepted: 08/06/2019] [Indexed: 10/26/2022]
Abstract
Moths and butterflies (Lepidoptera) are the most species-rich group of animals with female heterogamety, females mostly having a WZ, males a ZZ sex chromosome constitution. We studied chromatin conformation, activity, and inactivity of the sex chromosomes in the flour moth Ephestia kuehniella and the silkworm Bombyx mori, using immunostaining with anti-H3K9me2/3, anti-RNA polymerase II, and fluoro-uridine (FU) labelling of nascent transcripts, with conventional widefield fluorescence microscopy and 'spatial structured illumination microscopy' (3D-SIM). The Z chromosome is euchromatic in somatic cells and throughout meiosis. It is transcriptionally active in somatic cells and in the postpachaytene stage of meiosis. The W chromosome in contrast is heterochromatic in somatic cells as well as in meiotic cells at pachytene, but euchromatic and transcriptionally active like all other chromosomes at postpachytene. As the W chromosomes are apparently devoid of protein-coding genes, their transcripts must be non-coding. We found no indication of 'meiotic sex chromosome inactivation' (MSCI) in the two species.
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Wang Y, Zhao Q, Wan QX, Wang KX, Zha XF. P-element Somatic Inhibitor Protein Binding a Target Sequence in dsx Pre-mRNA Conserved in Bombyx mori and Spodoptera litura. Int J Mol Sci 2019; 20:ijms20092361. [PMID: 31086020 PMCID: PMC6539025 DOI: 10.3390/ijms20092361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/10/2019] [Accepted: 05/10/2019] [Indexed: 02/06/2023] Open
Abstract
Bombyx mori doublesex (Bmdsx) functions as a double-switch gene in the final step of the sex-determination cascade in the silkworm Bombyx mori. The P-element somatic inhibitor (PSI) protein in B. mori interacts with Bmdsx pre-mRNA in CE1 as an exonic splicing silencer to promote male-specific splicing of Bmdsx. However, the character of the interaction between BmPSI and Bmdsx pre-mRNA remains unclear. Electrophoretic mobility shift assay (EMSA) results showed that the four KH_1 motifs in BmPSI are all essential for the binding, especially the former two KH_1 motifs. Three active sites (I116, L127, and IGGI) in the KH_1 motif were found to be necessary for the binding through EMSA, circular dichroism (CD) spectroscopy, and isothermal titration calorimetry (ITC). The PSI homologous protein in S. litura (SlPSI) was purified and the binding of SlPSI and CE1 was verified. Compared with BmPSI, the mutant SlPSI proteins of I116 and IGGI lost their ability to bind to CE1. In conclusion, the binding of PSI and dsx pre-mRNA are generally conserved in both B. mori and S. litura. These findings provide clues for sex determination in Lepidoptera.
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Affiliation(s)
- Yao Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China.
| | - Qin Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China.
| | - Qiu-Xing Wan
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China.
| | - Kai-Xuan Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China.
| | - Xing-Fu Zha
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China.
- Chongqing Key Laboratory of Sericultural Science, Southwest University, Chongqing 400715, China.
- Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, China.
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Kawamoto M, Jouraku A, Toyoda A, Yokoi K, Minakuchi Y, Katsuma S, Fujiyama A, Kiuchi T, Yamamoto K, Shimada T. High-quality genome assembly of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 107:53-62. [PMID: 30802494 DOI: 10.1016/j.ibmb.2019.02.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 02/13/2019] [Accepted: 02/18/2019] [Indexed: 05/21/2023]
Abstract
In 2008, the genome assembly and gene models for the domestic silkworm, Bombyx mori, were published by a Japanese and Chinese collaboration group. However, the genome assembly contains a non-negligible number of misassembled and gap regions due to the presence of many repetitive sequences within the silkworm genome. The erroneous genome assembly occasionally causes incorrect gene prediction. Here we performed hybrid assembly based on 140 × deep sequencing of long (PacBio) and short (Illumina) reads. The remaining gaps in the initial genome assembly were closed using BAC and Fosmid sequences, giving a new total length of 460.3 Mb, with 30 gap regions and an N50 comprising 16.8 Mb in scaffolds and 12.2 Mb in contigs. More RNA-seq and piRNA-seq reads were mapped on the new genome assembly compared with the previous version, indicating that the new genome assembly covers more transcribed regions, including repetitive elements. We performed gene prediction based on the new genome assembly using available mRNA and protein sequence data. The number of gene models was 16,880 with an N50 of 2154 bp. The new gene models reflected more accurate coding sequences and gene sets than old ones. The proportion of repetitive elements was also reestimated using the new genome assembly, and was calculated to be 46.8% in the silkworm genome. The new genome assembly and gene models are provided in SilkBase (http://silkbase.ab.a.u-tokyo.ac.jp).
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Affiliation(s)
- Munetaka Kawamoto
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Akiya Jouraku
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan; Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Kakeru Yokoi
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Yohei Minakuchi
- Comparative Genomics Laboratory, Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Asao Fujiyama
- Comparative Genomics Laboratory, Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan; Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
| | - Kimiko Yamamoto
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan.
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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20
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Li S, Ajimura M, Chen Z, Liu J, Chen E, Guo H, Tadapatri V, Reddy CG, Zhang J, Kishino H, Abe H, Xia Q, Arunkumar KP, Mita K. A new approach for comprehensively describing heterogametic sex chromosomes. DNA Res 2018; 25:375-382. [PMID: 29617732 PMCID: PMC6105102 DOI: 10.1093/dnares/dsy010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/09/2018] [Indexed: 12/30/2022] Open
Abstract
Notwithstanding the rapid developments in sequencing techniques, Y and W sex chromosomes have still been mostly excluded from whole genome sequencing projects due to their high repetitive DNA content. Therefore, Y and W chromosomes are poorly described in most species despite their biological importance. Several methods were developed for identifying Y or W-linked sequences among unmapped scaffolds. However, it is not enough to discover functional regions from short unmapped scaffolds. Here, we provide a new and simple strategy based on k-mer comparison for comprehensive analysis of the W chromosome in Bombyx mori. Using this novel method, we effectively assembled de novo 1281 W-derived genome contigs (totaling 1.9 Mbp), and identified 156 W-linked transcript RNAs and 345 W-linked small RNAs. This method will help in the elucidation of mechanisms of sexual development and exploration of W chromosome biological functions, and provide insights into the evolution of sex chromosomes. Moreover, we showed this method can be employed in identifying heterogametic sex chromosomes (W and Y chromosomes) in many other species where genomic information is still scarce.
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Affiliation(s)
- Shenglong Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Masahiro Ajimura
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Zhiwei Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Jianqiu Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Enxiang Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Huizhen Guo
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Vidya Tadapatri
- Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telengana, India
| | - Chilakala Gangi Reddy
- Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telengana, India
| | - Jiwei Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Hirohisa Kishino
- Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
| | - Hiroaki Abe
- Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Kallare P Arunkumar
- Laboratory of Molecular Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telengana, India
| | - Kazuei Mita
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
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21
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Zhao S, Sun J, Shimizu K, Kadota K. Silhouette Scores for Arbitrary Defined Groups in Gene Expression Data and Insights into Differential Expression Results. Biol Proced Online 2018; 20:5. [PMID: 29507534 PMCID: PMC5831220 DOI: 10.1186/s12575-018-0067-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/12/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hierarchical Sample clustering (HSC) is widely performed to examine associations within expression data obtained from microarrays and RNA sequencing (RNA-seq). Researchers have investigated the HSC results with several possible criteria for grouping (e.g., sex, age, and disease types). However, the evaluation of arbitrary defined groups still counts in subjective visual inspection. RESULTS To objectively evaluate the degree of separation between groups of interest in the HSC dendrogram, we propose to use Silhouette scores. Silhouettes was originally developed as a graphical aid for the validation of data clusters. It provides a measure of how well a sample is classified when it was assigned to a cluster by according to both the tightness of the clusters and the separation between them. It ranges from 1.0 to - 1.0, and a larger value for the average silhouette (AS) over all samples to be analyzed indicates a higher degree of cluster separation. The basic idea to use an AS is to replace the term cluster by group when calculating the scores. We investigated the validity of this score using simulated and real data designed for differential expression (DE) analysis. We found that larger (or smaller) AS values agreed well with both higher (or lower) degrees of separation between different groups and higher percentages of differentially expressed genes (PDEG). We also found that the AS values were generally independent on the number of replicates (Nrep). Although the PDEG values depended on Nrep, we confirmed that both AS and PDEG values were close to zero when samples in the data showed an intermingled nature between the groups in the HSC dendrogram. CONCLUSION Silhouettes is useful for exploring data with predefined group labels. It would help provide both an objective evaluation of HSC dendrograms and insights into the DE results with regard to the compared groups.
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Affiliation(s)
- Shitao Zhao
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Jianqiang Sun
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Kentaro Shimizu
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Koji Kadota
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan
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Li Z, You L, Yan D, James AA, Huang Y, Tan A. Bombyx mori histone methyltransferase BmAsh2 is essential for silkworm piRNA-mediated sex determination. PLoS Genet 2018; 14:e1007245. [PMID: 29474354 PMCID: PMC5841826 DOI: 10.1371/journal.pgen.1007245] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 03/07/2018] [Accepted: 02/09/2018] [Indexed: 01/02/2023] Open
Abstract
Sex determination is a hierarchically-regulated process with high diversity in different organisms including insects. The W chromosome-derived Fem piRNA has been identified as the primary sex determination factor in the lepidopteran insect, Bombyx mori, revealing a distinctive piRNA-mediated sex determination pathway. However, the comprehensive mechanism of silkworm sex determination is still poorly understood. We show here that the silkworm PIWI protein BmSiwi, but not BmAgo3, is essential for silkworm sex determination. CRISPR/Cas9-mediated depletion of BmSiwi results in developmental arrest in oogenesis and partial female sexual reversal, while BmAgo3 depletion only affects oogenesis. We identify three histone methyltransferases (HMTs) that are significantly down-regulated in BmSiwi mutant moths. Disruption one of these, BmAsh2, causes dysregulation of piRNAs and transposable elements (TEs), supporting a role for it in the piRNA signaling pathway. More importantly, we find that BmAsh2 mutagenesis results in oogenesis arrest and partial female-to-male sexual reversal as well as dysregulation of the sex determination genes, Bmdsx and BmMasc. Mutagenesis of other two HMTs, BmSETD2 and BmEggless, does not affect piRNA-mediated sex determination. Histological analysis and immunoprecipitation results support a functional interaction between the BmAsh2 and BmSiwi proteins. Our data provide the first evidence that the HMT, BmAsh2, plays key roles in silkworm piRNA-mediated sex determination.
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Affiliation(s)
- Zhiqian Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Lang You
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Dong Yan
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Anthony A. James
- Departments of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California, United States of America
| | - Yongping Huang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Anjiang Tan
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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Fu Y, Yang Y, Zhang H, Farley G, Wang J, Quarles KA, Weng Z, Zamore PD. The genome of the Hi5 germ cell line from Trichoplusia ni, an agricultural pest and novel model for small RNA biology. eLife 2018; 7:31628. [PMID: 29376823 PMCID: PMC5844692 DOI: 10.7554/elife.31628] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/26/2018] [Indexed: 12/30/2022] Open
Abstract
We report a draft assembly of the genome of Hi5 cells from the lepidopteran insect pest, Trichoplusia ni, assigning 90.6% of bases to one of 28 chromosomes and predicting 14,037 protein-coding genes. Chemoreception and detoxification gene families reveal T. ni-specific gene expansions that may explain its widespread distribution and rapid adaptation to insecticides. Transcriptome and small RNA data from thorax, ovary, testis, and the germline-derived Hi5 cell line show distinct expression profiles for 295 microRNA- and >393 piRNA-producing loci, as well as 39 genes encoding small RNA pathway proteins. Nearly all of the W chromosome is devoted to piRNA production, and T. ni siRNAs are not 2´-O-methylated. To enable use of Hi5 cells as a model system, we have established genome editing and single-cell cloning protocols. The T. ni genome provides insights into pest control and allows Hi5 cells to become a new tool for studying small RNAs ex vivo. A common moth called the cabbage looper is becoming increasingly relevant to the scientific community. Its caterpillars are a serious threat to cabbage, broccoli and cauliflower crops, and they have started to resist the pesticides normally used to control them. Moreover, the insect’s germline cells – the ones that will produce sperm and eggs – are used in laboratories as ‘factories’ to artificially produce proteins of interest. The germline cells also host a group of genetic mechanisms called RNA silencing. One of these processes is known as piRNA, and it protects the genome against ‘jumping genes’. These genetic elements can cause mutations by moving from place to place in the DNA: in germline cells, piRNA suppresses them before the genetic information is transmitted to the next generation. Not all germline cells grow equally well under experimental conditions, or are easy to use to examine piRNA mechanisms in a laboratory. The germline cells from the cabbage looper, on the other hand, have certain characteristics that would make them ideal to study piRNA in insects. However, the genome of the moth had not yet been fully resolved. This hinders research on new ways of controlling the pest, on how to use the germline cells to produce more useful proteins, or on piRNA. Decoding a genome requires several steps. First, the entire genetic information is broken in short sections that can then be deciphered. Next, these segments need to be ‘assembled’ – put together, and in the right order, to reconstitute the entire genome. Certain portions of the genome, which are formed of repeats of the same sections, can be difficult to assemble. Finally, the genome must be annotated: the different regions – such as the genes – need to be identified and labeled. Here, Fu et al. assembled and annotated the genome of the cabbage looper, and in the process developed strategies that could be used for other species with a lot of repeated sequences in their genomes. Having access to the looper’s full genetic information makes it possible to use their germline cells to produce new types of proteins, for example for pharmaceutical purposes. Fu et al. went on to make working with these cells even easier by refining protocols so that modern research techniques, such as the gene-editing technology CRISPR-Cas9, can be used on the looper germline cells. The mapping of the genome also revealed that the genes involved in removing toxins from the insects’ bodies are rapidly evolving, which may explain why the moths readily become resistant to insecticides. This knowledge could help finding new ways of controlling the pest. Finally, the genes involved in RNA silencing were labeled: results show that an entire chromosome is the source of piRNAs. Combined with the new protocols developed by Fu et al., this could make cabbage looper germline cells the default option for any research into the piRNA mechanism. How piRNA works in the moth could inform work on human piRNA, as these processes are highly similar across the animal kingdom.
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Affiliation(s)
- Yu Fu
- Bioinformatics Program, Boston University, Boston, United States.,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, United States
| | - Yujing Yang
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
| | - Han Zhang
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
| | - Gwen Farley
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
| | - Junling Wang
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
| | - Kaycee A Quarles
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, United States
| | - Phillip D Zamore
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, United States
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Sex Determination Cascade in Insects: A Great Treasure House of Alternative Splicing. DIVERSITY AND COMMONALITY IN ANIMALS 2018. [DOI: 10.1007/978-4-431-56609-0_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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KATSUMA S, KIUCHI T, KAWAMOTO M, FUJIMOTO T, SAHARA K. Unique sex determination system in the silkworm, Bombyx mori: current status and beyond. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:205-216. [PMID: 29760316 PMCID: PMC6021594 DOI: 10.2183/pjab.94.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 02/19/2018] [Indexed: 06/02/2023]
Abstract
The silkworm Bombyx mori has been used for silk production for over 5,000 years. In addition to its contribution to sericulture, B. mori has played an important role in the field of genetics. Classical genetic studies revealed that a gene(s) with a strong feminizing activity is located on the W chromosome, but this W-linked feminizing gene, called Feminizer (Fem), had not been cloned despite more than 80 years of study. In 2014, we discovered that Fem is a precursor of a single W chromosome-derived PIWI-interacting RNA (piRNA). Fem-derived piRNA binds to PIWI protein, and this complex then cleaves the mRNA of the Z-linked Masculinizer (Masc) gene, which encodes a protein required for both masculinization and dosage compensation. These findings showed that the piRNA-mediated interaction between the two sex chromosomes is the primary signal for the sex determination cascade in B. mori. In this review, we summarize the history, current status, and perspective of studies on sex determination and related topics in B. mori.
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Affiliation(s)
- Susumu KATSUMA
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takashi KIUCHI
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Munetaka KAWAMOTO
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Toshiaki FUJIMOTO
- Laboratory of Applied Entomology, Faculty of Agriculture, Iwate University, Iwate, Japan
| | - Ken SAHARA
- Laboratory of Applied Entomology, Faculty of Agriculture, Iwate University, Iwate, Japan
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Shoji K, Suzuki Y, Sugano S, Shimada T, Katsuma S. Artificial "ping-pong" cascade of PIWI-interacting RNA in silkworm cells. RNA (NEW YORK, N.Y.) 2017; 23:86-97. [PMID: 27777367 PMCID: PMC5159652 DOI: 10.1261/rna.058875.116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/15/2016] [Indexed: 05/19/2023]
Abstract
PIWI-interacting RNAs (piRNAs) play essential roles in the defense system against selfish elements in animal germline cells by cooperating with PIWI proteins. A subset of piRNAs is predicted to be generated via the "ping-pong" cascade, which is mainly controlled by two different PIWI proteins. Here we established a cell-based artificial piRNA production system using a silkworm ovarian cultured cell line that is believed to possess a complete piRNA pathway. In addition, we took advantage of a unique silkworm sex-determining one-to-one ping-pong piRNA pair, which enabled us to precisely monitor the behavior of individual artificial piRNAs. With this novel strategy, we successfully generated artificial piRNAs against endogenous protein-coding genes via the expected back-and-forth traveling mechanism. Furthermore, we detected "primary" piRNAs from the upstream region of the artificial "ping-pong" site in the endogenous gene. This artificial piRNA production system experimentally confirms the existence of the "ping-pong" cascade of piRNAs. Also, this system will enable us to identify the factors involved in both, or each, of the "ping" and "pong" cascades and the sequence features that are required for efficient piRNA production.
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Affiliation(s)
- Keisuke Shoji
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-0882, Japan
| | - Sumio Sugano
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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27
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Sakai H, Sumitani M, Chikami Y, Yahata K, Uchino K, Kiuchi T, Katsuma S, Aoki F, Sezutsu H, Suzuki MG. Transgenic Expression of the piRNA-Resistant Masculinizer Gene Induces Female-Specific Lethality and Partial Female-to-Male Sex Reversal in the Silkworm, Bombyx mori. PLoS Genet 2016; 12:e1006203. [PMID: 27579676 PMCID: PMC5007099 DOI: 10.1371/journal.pgen.1006203] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/28/2016] [Indexed: 12/12/2022] Open
Abstract
In Bombyx mori (B. mori), Fem piRNA originates from the W chromosome and is responsible for femaleness. The Fem piRNA-PIWI complex targets and cleaves mRNAs transcribed from the Masc gene. Masc encodes a novel CCCH type zinc-finger protein and is required for male-specific splicing of B. mori doublesex (Bmdsx) transcripts. In the present study, several silkworm strains carrying a transgene, which encodes a Fem piRNA-resistant Masc mRNA (Masc-R), were generated. Forced expression of the Masc-R transgene caused female-specific lethality during the larval stages. One of the Masc-R strains weakly expressed Masc-R in various tissues. Females heterozygous for the transgene expressed male-specific isoform of the Bombyx homolog of insulin-like growth factor II mRNA-binding protein (ImpM) and Bmdsx. All examined females showed a lower inducibility of vitellogenin synthesis and exhibited abnormalities in the ovaries. Testis-like tissues were observed in abnormal ovaries and, notably, the tissues contained considerable numbers of sperm bundles. Homozygous expression of the transgene resulted in formation of the male-specific abdominal segment in adult females and caused partial male differentiation in female genitalia. These results strongly suggest that Masc is an important regulatory gene of maleness in B. mori.
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Affiliation(s)
- Hiroki Sakai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Megumi Sumitani
- Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Yasuhiko Chikami
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Kensuke Yahata
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Keiro Uchino
- Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Fugaku Aoki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Hideki Sezutsu
- Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Masataka G. Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
- * E-mail:
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28
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Sugano Y, Kokusho R, Ueda M, Fujimoto M, Tsutsumi N, Shimada T, Kiuchi T, Katsuma S. Identification of a bipartite nuclear localization signal in the silkworm Masc protein. FEBS Lett 2016; 590:2256-61. [DOI: 10.1002/1873-3468.12246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 05/30/2016] [Accepted: 05/30/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Yudai Sugano
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Ryuhei Kokusho
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Masamichi Ueda
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Masaru Fujimoto
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Nobuhiro Tsutsumi
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; Japan
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29
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Śliwińska EB, Martyka R, Tryjanowski P. Evolutionary interaction between W/Y chromosome and transposable elements. Genetica 2016; 144:267-78. [PMID: 27000053 PMCID: PMC4879163 DOI: 10.1007/s10709-016-9895-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 03/13/2016] [Indexed: 11/28/2022]
Abstract
The W/Y chromosome is unique among chromosomes as it does not recombine in its mature form. The main side effect of cessation of recombination is evolutionary instability and degeneration of the W/Y chromosome, or frequent W/Y chromosome turnovers. Another important feature of W/Y chromosome degeneration is transposable element (TEs) accumulation. Transposon accumulation has been confirmed for all W/Y chromosomes that have been sequenced so far. Models of W/Y chromosome instability include the assemblage of deleterious mutations in protein coding genes, but do not include the influence of transposable elements that are accumulated gradually in the non-recombining genome. The multiple roles of genomic TEs, and the interactions between retrotransposons and genome defense proteins are currently being studied intensively. Small RNAs originating from retrotransposon transcripts appear to be, in some cases, the only mediators of W/Y chromosome function. Based on the review of the most recent publications, we present knowledge on W/Y evolution in relation to retrotransposable element accumulation.
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Affiliation(s)
- Ewa B Śliwińska
- Institute of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, 60-625, Poznań, Poland.
- Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120, Kraków, Poland.
| | - Rafał Martyka
- Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120, Kraków, Poland
| | - Piotr Tryjanowski
- Institute of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, 60-625, Poznań, Poland
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Wu Y, Cheng T, Liu C, Liu D, Zhang Q, Long R, Zhao P, Xia Q. Systematic Identification and Characterization of Long Non-Coding RNAs in the Silkworm, Bombyx mori. PLoS One 2016; 11:e0147147. [PMID: 26771876 PMCID: PMC4714849 DOI: 10.1371/journal.pone.0147147] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/22/2015] [Indexed: 02/04/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) are emerging as important regulators in various biological processes. However, to date, no systematic characterization of lncRNAs has been reported in the silkworm Bombyx mori. In the present study, we generated eighteen RNA-seq datasets with relatively high depth. Using an in-house designed lncRNA identification pipeline, 11,810 lncRNAs were identified for 5,556 loci. Among these lncRNAs, 474 transcripts were intronic lncRNAs (ilncRNAs), 6,250 transcripts were intergenic lncRNAs (lincRNAs), and 5,086 were natural antisense lncRNAs (lncNATs). Compared with protein-coding mRNAs, silkworm lncRNAs are shorter in terms of full length but longer in terms of exon and intron length. In addition, lncRNAs exhibit a lower level of sequence conservation, more repeat sequences overlapped and higher tissue specificity than protein-coding mRNAs in the silkworm. We found that 69 lncRNA transcripts from 33 gene loci may function as miRNA precursors, and 104 lncRNA transcripts from 72 gene loci may act as competing endogenous RNAs (ceRNAs). In total, 49.47% of all gene loci (2,749/5,556) for which lncRNAs were identified showed sex-biased expression. Co-expression network analysis resulted in 19 modules, 12 of which revealed relatively high tissue specificity. The highlighted darkgoldenrod module was specifically associated with middle and posterior silk glands, and the hub lncRNAs within this module were co-expressed with proteins involved in translation, translocation, and secretory processes, suggesting that these hub lncRNAs may function as regulators of the biosynthesis, translocation, and secretion of silk proteins. This study presents the first comprehensive genome-wide analysis of silkworm lncRNAs and provides an invaluable resource for genetic, evolutionary, and genomic studies of B. mori.
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Affiliation(s)
- Yuqian Wu
- School of Life Sciences, Chongqing University, Chongqing 400044, China
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Duolian Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Quan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Renwen Long
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
- * E-mail:
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Lim RSM, Kai T. A piece of the pi(e): The diverse roles of animal piRNAs and their PIWI partners. Semin Cell Dev Biol 2015; 47-48:17-31. [PMID: 26582251 DOI: 10.1016/j.semcdb.2015.10.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Small non-coding RNAs are indispensable to many biological processes. A class of endogenous small RNAs, termed PIWI-interacting RNAs (piRNAs) because of their association with PIWI proteins, has known roles in safeguarding the genome against inordinate transposon mobilization, embryonic development, and stem cell regulation, among others. This review discusses the biogenesis of animal piRNAs and their diverse functions together with their PIWI protein partners, both in the germline and in somatic cells, and highlights the evolutionarily conserved aspects of these molecular players in animal biology.
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Affiliation(s)
- Robyn S M Lim
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
| | - Toshie Kai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
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Abstract
The W chromosome of the silkworm Bombyx mori has been known to determine femaleness for more than 80 years. However, the feminizing gene has not been molecularly identified, because the B. mori W chromosome is almost fully occupied by a large number of transposable elements. The W chromosome-derived feminizing factor of B. mori was recently shown to be a female-specific PIWI-interacting RNA (piRNA). piRNAs are small RNAs that potentially repress invading “non-self” elements (e.g., transposons and virus-like elements) by associating with PIWI proteins. Our results revealed that female-specific piRNA precursors, which we named Fem, are transcribed from the sex-determining region of the W chromosome at the early embryonic stage and are processed into a single mature piRNA (Fem piRNA). Fem piRNA forms a complex with Siwi (silkworm Piwi), which cleaves a protein-coding mRNA transcribed from the Z chromosome. RNA interference of this Z-linked gene, which we named Masc, revealed that this gene encodes a protein required for masculinization and dosage compensation. Fem and Masc both participate in the ping-pong cycle of the piRNA amplification loop by associating with the 2 B. mori PIWI proteins Siwi and BmAgo3 (silkworm Ago3), respectively, indicating that the piRNA-mediated interaction between the 2 sex chromosomes is the primary signal for the B. mori sex determination cascade. Fem is a non-transposable repetitive sequence on the W chromosome, whereas Masc is a single-copy protein-coding gene. It is of great interest how the piRNA system recognizes “self ”Masc mRNA as “non-self” RNA.
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Affiliation(s)
- Susumu Katsuma
- a Department of Agricultural and Environmental Biology; Graduate School of Agricultural and Life Sciences ; The University of Tokyo ; Bunkyo-ku , Tokyo , Japan
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Katsuma S, Sugano Y, Kiuchi T, Shimada T. Two Conserved Cysteine Residues Are Required for the Masculinizing Activity of the Silkworm Masc Protein. J Biol Chem 2015; 290:26114-24. [PMID: 26342076 DOI: 10.1074/jbc.m115.685362] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Indexed: 11/06/2022] Open
Abstract
We have recently discovered that the Masculinizer (Masc) gene encodes a CCCH tandem zinc finger protein, which controls both masculinization and dosage compensation in the silkworm Bombyx mori. In this study, we attempted to identify functional regions or residues that are required for the masculinizing activity of the Masc protein. We constructed a series of plasmids that expressed the Masc derivatives and transfected them into a B. mori ovary-derived cell line, BmN-4. To assess the masculinizing activity of the Masc derivatives, we investigated the splicing patterns of B. mori doublesex (Bmdsx) and the expression levels of B. mori IGF-II mRNA-binding protein, a splicing regulator of Bmdsx, in Masc cDNA-transfected BmN-4 cells. We found that two zinc finger domains are not required for the masculinizing activity. We also identified that the C-terminal 288 amino acid residues are sufficient for the masculinizing activity of the Masc protein. Further detailed analyses revealed that two cysteine residues, Cys-301 and Cys-304, in the highly conserved region among lepidopteran Masc proteins are essential for the masculinizing activity in BmN-4 cells. Finally, we showed that Masc is a nuclear protein, but its nuclear localization is not tightly associated with the masculinizing activity.
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Affiliation(s)
- Susumu Katsuma
- From the Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yudai Sugano
- From the Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takashi Kiuchi
- From the Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toru Shimada
- From the Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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Kawamoto M, Koga H, Kiuchi T, Shoji K, Sugano S, Shimada T, Suzuki Y, Katsuma S. Sexually biased transcripts at early embryonic stages of the silkworm depend on the sex chromosome constitution. Gene 2015; 560:50-6. [PMID: 25615878 DOI: 10.1016/j.gene.2015.01.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 12/18/2014] [Accepted: 01/20/2015] [Indexed: 11/24/2022]
Abstract
In the silkworm, Bombyx mori, females are heterogametic (WZ) whereas males have two Z chromosomes. Femaleness of B. mori is determined by the presence of the W chromosome, suggesting that there is a dominant feminizing gene on this chromosome. Recently, by transcriptome analysis of B. mori embryos, we discovered that a single W-chromosome-derived PIWI-interacting RNA (piRNA) is the long-sought primary determinant of femaleness in B. mori. However, sexual bias in the transcriptome of B. mori early embryos has not yet been well characterized. Using deep sequencing data from molecularly sexed RNA of B. mori embryos, we identified and characterized 157 transcripts that are statistically differentially expressed between male and female early embryos. Most of the female-biased transcripts were transposons or repeat sequences that are produced presumably from the W chromosome. Bioinformatic analysis revealed that these repetitive sequences are piRNA precursors. In contrast, male-biased genes were frequently transcribed from the Z chromosome, suggesting that dosage compensation in Z-linked genes does not occur or is incomplete at early embryonic stages. Our analysis has drawn a picture of a global landscape of sexually biased transcriptome during early B. mori embyogenesis and has suggested for the first time that most sexually biased embryonic transcripts depend on sex chromosomes.
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Affiliation(s)
- Munetaka Kawamoto
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hikaru Koga
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Keisuke Shoji
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Sumio Sugano
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yutaka Suzuki
- Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
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Kolliopoulou A, Swevers L. Recent progress in RNAi research in Lepidoptera: intracellular machinery, antiviral immune response and prospects for insect pest control. CURRENT OPINION IN INSECT SCIENCE 2014; 6:28-34. [PMID: 0 DOI: 10.1016/j.cois.2014.09.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/27/2014] [Accepted: 09/30/2014] [Indexed: 05/03/2023]
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Jing J, Wu J, Liu W, Xiong S, Ma W, Zhang J, Wang W, Gui JF, Mei J. Sex-biased miRNAs in gonad and their potential roles for testis development in yellow catfish. PLoS One 2014; 9:e107946. [PMID: 25229553 PMCID: PMC4168133 DOI: 10.1371/journal.pone.0107946] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/17/2014] [Indexed: 12/21/2022] Open
Abstract
Recently, YY super-male yellow catfish had been created by hormonal-induced sex reversal and sex-linked markers, which provides a promising research model for fish sex differentiation and gonad development, especially for testis development. MicroRNAs (miRNAs) have been revealed to play crucial roles in the gene regulation and gonad development in vertebrates. In this study, three small RNA libraries constructed from gonad tissues of XX female, XY male and YY super-male yellow catfish were sequenced. The sequencing data generated a total of 384 conserved miRNAs and 113 potential novel miRNAs, among which 23, 30 and 14 miRNAs were specifically detected in XX ovary, XY testis, and YY testis, respectively. We observed relative lower expression of several miR-200 family members, including miR-141 and miR-429 in YY testis compared with XY testis. Histological analysis indicated a higher degree of testis maturity in YY super-males compared with XY males, as shown by larger spermatogenic cyst, more spermatids and fewer spermatocytes in the spermatogenic cyst. Moreover, five miR-200 family members were significantly up-regulated in testis when treated by 17α-ethinylestradiol (EE2), high dose of which will impair testis development and cell proliferation. The down-regulation of miR-141 and 429 coincides with the progression of testis development in both yellow catfish and human. At last, the expression pattern of nine arbitrarily selected miRNAs detected by quantitative RT-PCR was consistent with the Solexa sequencing results. Our study provides a comprehensive miRNA transcriptome analysis for gonad of yellow catfish with different sex genotypes, and identifies a number of sex-biased miRNAs, some of that are potentially involved in testis development and spermatogenesis.
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Affiliation(s)
- Jing Jing
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Junjie Wu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Wei Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan, China
| | - Shuting Xiong
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Wenge Ma
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Jin Zhang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Weimin Wang
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Jian-Fang Gui
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan, China
- * E-mail: (JFG); (JM)
| | - Jie Mei
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Huazhong Agricultural University, Wuhan, China
- * E-mail: (JFG); (JM)
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A single female-specific piRNA is the primary determiner of sex in the silkworm. Nature 2014; 509:633-6. [PMID: 24828047 DOI: 10.1038/nature13315] [Citation(s) in RCA: 319] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 04/08/2014] [Indexed: 11/08/2022]
Abstract
The silkworm Bombyx mori uses a WZ sex determination system that is analogous to the one found in birds and some reptiles. In this system, males have two Z sex chromosomes, whereas females have Z and W sex chromosomes. The silkworm W chromosome has a dominant role in female determination, suggesting the existence of a dominant feminizing gene in this chromosome. However, the W chromosome is almost fully occupied by transposable element sequences, and no functional protein-coding gene has been identified so far. Female-enriched PIWI-interacting RNAs (piRNAs) are the only known transcripts that are produced from the sex-determining region of the W chromosome, but the function(s) of these piRNAs are unknown. Here we show that a W-chromosome-derived, female-specific piRNA is the feminizing factor of B. mori. This piRNA is produced from a piRNA precursor which we named Fem. Fem sequences were arranged in tandem in the sex-determining region of the W chromosome. Inhibition of Fem-derived piRNA-mediated signalling in female embryos led to the production of the male-specific splice variants of B. mori doublesex (Bmdsx), a gene which acts at the downstream end of the sex differentiation cascade. A target gene of Fem-derived piRNA was identified on the Z chromosome of B. mori. This gene, which we named Masc, encoded a CCCH-type zinc finger protein. We show that the silencing of Masc messenger RNA by Fem piRNA is required for the production of female-specific isoforms of Bmdsx in female embryos, and that Masc protein controls both dosage compensation and masculinization in male embryos. Our study characterizes a single small RNA that is responsible for primary sex determination in the WZ sex determination system.
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Silkworm sex factor is no ordinary gene. Nature 2014. [DOI: 10.1038/nature.2014.15221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nagaraju J, Gopinath G, Sharma V, Shukla J. Lepidopteran Sex Determination: A Cascade of Surprises. Sex Dev 2014; 8:104-12. [DOI: 10.1159/000357483] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Nie Z, Zhou F, Li D, Lv Z, Chen J, Liu Y, Shu J, Sheng Q, Yu W, Zhang W, Jiang C, Yao Y, Yao J, Jin Y, Zhang Y. RIP-seq of BmAgo2-associated small RNAs reveal various types of small non-coding RNAs in the silkworm, Bombyx mori. BMC Genomics 2013; 14:661. [PMID: 24074203 PMCID: PMC3849828 DOI: 10.1186/1471-2164-14-661] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 09/26/2013] [Indexed: 12/21/2022] Open
Abstract
Background Small non-coding RNAs (ncRNAs) are important regulators of gene expression in eukaryotes. Previously, only microRNAs (miRNAs) and piRNAs have been identified in the silkworm, Bombyx mori. Furthermore, only ncRNAs (50-500nt) of intermediate size have been systematically identified in the silkworm. Results Here, we performed a systematic identification and analysis of small RNAs (18-50nt) associated with the Bombyx mori argonaute2 (BmAgo2) protein. Using RIP-seq, we identified various types of small ncRNAs associated with BmAGO2. These ncRNAs showed a multimodal length distribution, with three peaks at ~20nt, ~27nt and ~33nt, which included tRNA-, transposable element (TE)-, rRNA-, snoRNA- and snRNA-derived small RNAs as well as miRNAs and piRNAs. The tRNA-derived fragments (tRFs) were found at an extremely high abundance and accounted for 69.90% of the BmAgo2-associated small RNAs. Northern blotting confirmed that many tRFs were expressed or up-regulated only in the BmNPV-infected cells, implying that the tRFs play a prominent role by binding to BmAgo2 during BmNPV infection. Additional evidence suggested that there are potential cleavage sites on the D, anti-codon and TψC loops of the tRNAs. TE-derived small RNAs and piRNAs also accounted for a significant proportion of the BmAgo2-associated small RNAs, suggesting that BmAgo2 could be involved in the maintenance of genome stability by suppressing the activities of transposons guided by these small RNAs. Finally, Northern blotting was also used to confirm the Bombyx 5.8 s rRNA-derived small RNAs, demonstrating that various novel small RNAs exist in the silkworm. Conclusions Using an RIP-seq method in combination with Northern blotting, we identified various types of small RNAs associated with the BmAgo2 protein, including tRNA-, TE-, rRNA-, snoRNA- and snRNA-derived small RNAs as well as miRNAs and piRNAs. Our findings provide new clues for future functional studies of the role of small RNAs in insect development and evolution.
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Affiliation(s)
- Zuoming Nie
- College of Life Sciences, Zhejiang Sci-Tech University, Hanghzou 310018, China.
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Cai Y, Zhou Q, Yu C, Wang X, Hu S, Yu J, Yu X. Transposable-element associated small RNAs in Bombyx mori genome. PLoS One 2012; 7:e36599. [PMID: 22662121 PMCID: PMC3359762 DOI: 10.1371/journal.pone.0036599] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/06/2012] [Indexed: 11/18/2022] Open
Abstract
Small RNAs are a group of regulatory RNA molecules that control gene expression at transcriptional or post-transcriptional levels among eukaryotes. The silkworm, Bombyx mori L., genome harbors abundant repetitive sequences derived from families of retrotransposons and transposons, which together constitute almost half of the genome space and provide ample resource for biogenesis of the three major small RNA families. We systematically discovered transposable-element (TE)-associated small RNAs in B. mori genome based on a deep RNA-sequencing strategy and the effort yielded 182, 788 and 4,990 TE-associated small RNAs in the miRNA, siRNA and piRNA species, respectively. Our analysis suggested that the three small RNA species preferentially associate with different TEs to create sequence and functional diversity, and we also show evidence that a Bombyx non-LTR retrotransposon, bm1645, alone contributes to the generation of TE-associated small RNAs in a very significant way. The fact that bm1645-associated small RNAs partially overlap with each other implies a possibility that this element may be modulated by different mechanisms to generate different products with diverse functions. Taken together, these discoveries expand the small RNA pool in B. mori genome and lead to new knowledge on the diversity and functional significance of TE-associated small RNAs.
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Affiliation(s)
- Yimei Cai
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Qing Zhou
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Caixia Yu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Xumin Wang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Songnian Hu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Jun Yu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (JY); (XY)
| | - Xiaomin Yu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JY); (XY)
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Hara K, Fujii T, Suzuki Y, Sugano S, Shimada T, Katsuma S, Kawaoka S. Altered expression of testis-specific genes, piRNAs, and transposons in the silkworm ovary masculinized by a W chromosome mutation. BMC Genomics 2012; 13:119. [PMID: 22452797 PMCID: PMC3342102 DOI: 10.1186/1471-2164-13-119] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 03/28/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the silkworm, Bombyx mori, femaleness is strongly controlled by the female-specific W chromosome. Originally, it was presumed that the W chromosome encodes female-determining gene(s), accordingly called Fem. However, to date, neither Fem nor any protein-coding gene has been identified from the W chromosome. Instead, the W chromosome is occupied with numerous transposon-related sequences. Interestingly, the silkworm W chromosome is a source of female-enriched PIWI-interacting RNAs (piRNAs). piRNAs are small RNAs of 23-30 nucleotides in length, which are required for controlling transposon activity in animal gonads. A recent study has identified a novel mutant silkworm line called KG, whose mutation in the W chromosome causes severe female masculinization. However, the molecular nature of KG line has not been well characterized yet. RESULTS Here we molecularly characterize the KG line. Genomic PCR analyses using currently available W chromosome-specific PCR markers indicated that no large deletion existed in the KG W chromosome. Genetic analyses demonstrated that sib-crosses within the KG line suppressed masculinization. Masculinization reactivated when crossing KG females with wild type males. Importantly, the KG ovaries exhibited a significantly abnormal transcriptome. First, the KG ovaries misexpressed testis-specific genes. Second, a set of female-enriched piRNAs was downregulated in the KG ovaries. Third, several transposons were overexpressed in the KG ovaries. CONCLUSIONS Collectively, the mutation in the KG W chromosome causes broadly altered expression of testis-specific genes, piRNAs, and transposons. To our knowledge, this is the first study that describes a W chromosome mutant with such an intriguing phenotype.
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Affiliation(s)
- Kahori Hara
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Japan
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Kawaoka S, Mitsutake H, Kiuchi T, Kobayashi M, Yoshikawa M, Suzuki Y, Sugano S, Shimada T, Kobayashi J, Tomari Y, Katsuma S. A role for transcription from a piRNA cluster in de novo piRNA production. RNA (NEW YORK, N.Y.) 2012; 18:265-73. [PMID: 22194309 PMCID: PMC3264913 DOI: 10.1261/rna.029777.111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
PIWI-interacting RNAs (piRNAs) are at the heart of the nucleic acid-based adaptive immune system against transposons in animal gonads. To date, how the piRNA pathway senses an element as a substrate and how de novo piRNA production is initiated remain elusive. Here, by utilizing a GFP transgene, we screened and obtained clonal silkworm BmN4 cell lines producing massively amplified GFP-derived piRNAs capable of silencing GFP in trans. In multiple independent cell lines where GFP expression was silenced by the piRNA pathway, we detected a common transcript from an endogenous piRNA cluster, in which a part of the cluster is uniquely fused with an antisense GFP sequence. Bioinformatic analyses suggest that the fusion transcript is a source of GFP primary piRNAs. Our data implicate a role for transcription from a piRNA cluster in initiating de novo piRNA production against a new insertion.
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Affiliation(s)
- Shinpei Kawaoka
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hiroshi Mitsutake
- The United Graduate School of Agricultural Sciences, Tottori University, Koyama-cho, Minami 4-101, Tottori 680-8553, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Maki Kobayashi
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Mayu Yoshikawa
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Yutaka Suzuki
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Sumio Sugano
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Jun Kobayashi
- The United Graduate School of Agricultural Sciences, Tottori University, Koyama-cho, Minami 4-101, Tottori 680-8553, Japan
- Faculty of Agriculture, Yamaguchi University, Yoshida 1677-1, Yamaguchi 753-8515, Japan
- Corresponding authors.E-mail .E-mail .E-mail .
| | - Yukihide Tomari
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
- Corresponding authors.E-mail .E-mail .E-mail .
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
- Corresponding authors.E-mail .E-mail .E-mail .
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