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Lv JL, Lai WQ, Gong YQ, Zheng KY, Zhang XY, Wang XY, Dai LS, Li MW. Studying the role of Bombyx mori molybdenum cofactor sulfurase in Bombyx mori nucleopolyhedrovirus infection. INSECT MOLECULAR BIOLOGY 2024; 33:246-258. [PMID: 38323672 DOI: 10.1111/imb.12895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/10/2024] [Indexed: 02/08/2024]
Abstract
Molybdenum cofactor sulfurase (MoCoS) is a key gene involved in the uric acid metabolic pathway that activates xanthine dehydrogenase to synthesise uric acid. Uric acid is harmful to mammals but plays crucial roles in insects, one of which is the immune responses. However, the function of Bombyx mori MoCoS in response to BmNPV remains unclear. In this study, BmMoCoS was found to be relatively highly expressed in embryonic development, gonads and the Malpighian tubules. In addition, the expression levels of BmMoCoS were significantly upregulated in three silkworm strains with different levels of resistance after virus infection, suggesting a close link between them. Furthermore, RNAi and overexpression studies showed that BmMoCoS was involved in resistance to BmNPV infection, and its antivirus effects were found to be related to the regulation of uric acid metabolism, which was uncovered by inosine- and febuxostat-coupled RNAi and overexpression. Finally, the BmMoCoS-mediated uric acid pathway was preliminarily confirmed to be a potential target to protect silkworms from BmNPV infection. Overall, this study provides new evidence for elucidating the molecular mechanism of silkworms in response to BmNPV infection and new strategies for the prevention of viral infections in sericulture.
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Affiliation(s)
- Jun-Li Lv
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
| | - Wen-Qing Lai
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
| | - Yu-Quan Gong
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
| | - Kai-Yi Zheng
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
| | - Xiao-Ying Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
| | - Xue-Yang Wang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu, China
| | - Li-Shang Dai
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Mu-Wang Li
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu, China
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2
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Tang L, Chen D, Yang D, Liu Z, Yang X, Liu Y, Zhang L, Liu Z, Wang Y, Tang Z, Huang Y. Bmpali, Bmb1 and Bmcap are necessary for uric acid granule formation in Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 167:104075. [PMID: 38278280 DOI: 10.1016/j.ibmb.2024.104075] [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: 11/22/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024]
Abstract
Uric acid is the end-product of nitrogen metabolism of the silkworm and other lepidopterans. The accumulation of uric acid particles in the epidermis causes the larval silkworm to appear white and opaque. However, the mechanism of uric acid granule formation is still unclear. Silkworm epidermis color is linked to the genes responsible for uric acid particle formation. We first identified two genes in the Bombyx mori genome that encode subunits of the Bloc-1 (Biogenesis of Lysosome-related Organelles Complex-1) by homology to these genes in other eukaryotes, Bmpali and Bmb1. Mutation in these genes caused a transparent phenotype in the silkworm larvae, and the loss of BmBloc-1 subunit gene Bmcap resulted in the same phenotype. These three genes are highly conserved between human and silkworm. We discovered that Bmpali, Bmcap, and Bmb1 localize in the cytoplasm of BmN cells. Yeast two-hybrid assays demonstrated that the Bmpali physically interacts with both Bmcap and Bmb1. Investigating the roles of Bmpali, Bmb1, and Bmcap is essential for uric acid granule formation understanding in Bombyx mori. These mutants present a valuable silkworm model for studying the biogenesis of lysosome-related organelles (LROs).
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Affiliation(s)
- Linmeng Tang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China; Central Research Institute, Shanghai Pharmaceuticals Holding Co., Ltd., Shanghai, China
| | - Dongbin Chen
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Dehong Yang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zhiwei Liu
- Departments of Neonatology, International Peace Maternity and Child Health Hospital of China Welfare Institution, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xu Yang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yujia Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Liying Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zulian Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yaohui Wang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zheng Tang
- Departments of Neonatology, International Peace Maternity and Child Health Hospital of China Welfare Institution, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
| | - Yongping Huang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China.
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3
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Wang L, Yin Y, Wang K, Cao J, Cheng T, Liu C, Zhang Y, Zhu Y. Bombyx mori monocarboxylate transporter 9 (BmMCT9) is involved in the transport of uric acid in silkworm integument. Genes Cells 2019; 25:33-40. [PMID: 31730247 DOI: 10.1111/gtc.12734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 11/04/2019] [Accepted: 11/13/2019] [Indexed: 12/17/2022]
Abstract
In Bombyx mori, there are more than 30 mutant strains exhibiting the translucent larval skin resulting from a decrease in the uric acid content in epidermal cell. Of these, the Chinese translucent (oc) mutant presents a moderately translucent larval skin. Previously, we narrowed the region linked to the oc phenotype to approximately 234 kb by positional cloning, and found that BmMCT9 was severely suppressed in the mutant. Here, we analyzed the mutation and potential molecular function of BmMCT9. Sequence analysis showed that a 2,624-bp fragment of BmMCT9 promoter region was replaced by a 22-bp sequence in the mutant. Luciferase reporter gene assay confirmed that BmMCT9 promoter activity in the mutant was significantly lower than that in the wild type. Knockdown of BmMCT9 caused a translucent phenotype in the first-instar silkworm larvae. Immunoblotting analysis showed that BmMCT9 expression was severely reduced in the mutant than in the wild type, and immunofluorescence showed that BmMCT9 existed mainly within the cytoplasm of epidermal cells. Together, our results suggest that reduced levels of BmMCT9 were responsible for the translucent phenotype of oc mutant, and that BmMCT9 might function in intracellular vesicles facing the cytoplasm including urate granules in silkworm integument.
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Affiliation(s)
- Lingyan Wang
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China.,Biological Science Research Center, Southwest University, Chongqing, China
| | - Yaru Yin
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China
| | - Kun Wang
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China
| | - Jun Cao
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China
| | - Yan Zhang
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China.,Biological Science Research Center, Southwest University, Chongqing, China
| | - Yong Zhu
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing, China
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Figon F, Casas J. Ommochromes in invertebrates: biochemistry and cell biology. Biol Rev Camb Philos Soc 2019; 94:156-183. [PMID: 29989284 DOI: 10.1111/brv.12441] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 06/09/2018] [Accepted: 06/12/2018] [Indexed: 01/24/2023]
Abstract
Ommochromes are widely occurring coloured molecules of invertebrates, arising from tryptophan catabolism through the so-called Tryptophan → Ommochrome pathway. They are mainly known to mediate compound eye vision, as well as reversible and irreversible colour patterning. Ommochromes might also be involved in cell homeostasis by detoxifying free tryptophan and buffering oxidative stress. These biological functions are directly linked to their unique chromophore, the phenoxazine/phenothiazine system. The most recent reviews on ommochrome biochemistry were published more than 30 years ago, since when new results on the enzymes of the ommochrome pathway, on ommochrome photochemistry as well as on their antiradical capacities have been obtained. Ommochromasomes are the organelles where ommochromes are synthesised and stored. Hence, they play an important role in mediating ommochrome functions. Ommochromasomes are part of the lysosome-related organelles (LROs) family, which includes other pigmented organelles such as vertebrate melanosomes. Ommochromasomes are unique because they are the only LRO for which a recycling process during reversible colour change has been described. Herein, we provide an update on ommochrome biochemistry, photoreactivity and antiradical capacities to explain their diversity and behaviour both in vivo and in vitro. We also highlight new biochemical techniques, such as quantum chemistry, metabolomics and crystallography, which could lead to major advances in their chemical and functional characterisation. We then focus on ommochromasome structure and formation by drawing parallels with the well-characterised melanosomes of vertebrates. The biochemical, genetic, cellular and microscopic tools that have been applied to melanosomes should provide important information on the ommochromasome life cycle. We propose LRO-based models for ommochromasome biogenesis and recycling that could be tested in the future. Using the context of insect compound eyes, we finally emphasise the importance of an integrated approach in understanding the biological functions of ommochromes.
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Affiliation(s)
- Florent Figon
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200 Tours, France
| | - Jérôme Casas
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200 Tours, France
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Wang L, Dong Z, Wang J, Yin Y, Liu H, Hu W, Peng Z, Liu C, Li M, Banno Y, Shimada T, Xia Q, Zhao P. Proteomic Analysis of Larval Integument in a Dominant Obese Translucent (Obs) Silkworm Mutant. JOURNAL OF INSECT SCIENCE (ONLINE) 2018; 18:5168485. [PMID: 30412263 PMCID: PMC6225826 DOI: 10.1093/jisesa/iey098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Indexed: 06/08/2023]
Abstract
The dominant obese translucent (Obs) mutant of the silkworm (Bombyx mori) results in a short and stout larval body, translucent phenotype, and abnormal pigmentation in the integument. The Obs mutant also displays deficiency in ecdysis and metamorphosis. In the present study, to gain an understanding of multiple Obs phenotypes, we investigated the phenotypes of Obs and performed a comparative analysis of the larval integument proteomes of Obs and normal silkworms. The phenotypic analysis revealed that the Obs larvae were indeed short and fat, and that chitin and uric acid content were lower but melanin content was higher in the Obs mutant. Proteomic analysis revealed that 244 proteins were significantly differentially expressed between Obs and normal silkworms, some of which were involved in uric acid metabolism and melanin pigmentation. Twenty-six proteins were annotated as cuticular proteins, including RR motif-rich cuticular proteins (CPR), glycine-rich cuticular protein (CPG), hypothetical cuticular protein (CPH), cuticular protein analogous to peritrophins (CPAPs), and the chitin_bind_3 motif proteins, and accounted for over 84% of the abundance of the total significantly differentially expressed proteins. Moreover, 22 of the 26 cuticular proteins were downregulated in the Obs mutant. Comparative proteomic analysis suggested that the multiple phenotypes of the Obs mutant might be related to changes in the expression of proteins that participate in cuticular formation, uric acid metabolism, and melanin pigmentation. These results could lay a basis for further identification of the gene responsible for the Obs mutant. The data have been deposited to ProteomeXchange with identifier PXD010998.
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Affiliation(s)
- Lingyan Wang
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Zhaoming Dong
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Juan Wang
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Yaru Yin
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Huawei Liu
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Wenbo Hu
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Zhangchuan Peng
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Muwang Li
- Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu, China
| | - Yutaka Banno
- Institute of Genetic Resources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Tiansheng Road, Beibei, Chongqing, China
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6
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Zhang H, Kiuchi T, Hirayama C, Banno Y, Katsuma S, Shimada T. A reexamination on the deficiency of riboflavin accumulation in Malpighian tubules in larval translucent mutants of the silkworm, Bombyx mori. Genetica 2018; 146:425-431. [PMID: 30094710 DOI: 10.1007/s10709-018-0034-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Accepted: 08/03/2018] [Indexed: 12/25/2022]
Abstract
A variety of insects accumulate high contents of riboflavin (vitamin B2) in their Malpighian tubules (MTs). Although this process is known to be genetically controlled, the mechanism is not known. In the 1940s and the 1950s, several studies showed that riboflavin contents were low in the MTs of some Bombyx mori (silkworm) mutants with translucent larval skin mutations (e.g., w-3, od, oa, and otm) and that genes responsible for these translucent mutations also affected riboflavin accumulation in the MTs. Since the 2000s, it has been shown that the w-3 gene encodes an ABC transporter, whereas genes responsible for od, oa, and otm mutations encode for the biogenesis of lysosome-related organelles. These findings suggest that some genes of ABC transporters and biogenesis of lysosome-related organelles may control the accumulation of riboflavin in MTs. Therefore, we reexamined the effects that translucent mutations have on the accumulation of riboflavin in MTs by using the translucent and wild-type segregants in mutant strains to measure the specific effect that each gene has on riboflavin accumulation (independent of genomic background). We used nine translucent mutations (w-3oe, oa, od, otm, Obs, oy, or, oh, and obt) even though the genes responsible for some of these mutations (Obs, oy, or, oh, and obt) have not yet been isolated. Through observation of larval MTs and measurements of riboflavin content using high-performance liquid chromatography, we found that the oa, od, otm, and or mutations were responsible for low contents of riboflavin in MTs, whereas the Obs and oy mutations did not affect riboflavin accumulation. This indicates that the molecular mechanism for riboflavin accumulation is similar but somewhat different than the mechanism responsible for uric acid accumulation in epidermal cells. We found that the genes responsible for oa, od, and otm mutations were consistent with those already established for uric acid accumulation in larval epidermis. This suggests that these three genes control riboflavin accumulation in MTs through a mechanism similar to that of uric acid accumulation, although we do not yet know why the or mutation also controls riboflavin accumulation.
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Affiliation(s)
- Haokun Zhang
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- School of Life Science, Fudan University, 2005 Songhu Road, Shanghai, 200438, China
| | - Takashi Kiuchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Chikara Hirayama
- National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Yutaka Banno
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki, Higashi-Ku, Fukuoka, 812-8581, Japan
| | - Susumu Katsuma
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Toru Shimada
- 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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Fujii T, Yamamoto K, Banno Y. Translucent larval integument and flaccid paralysis caused by genome editing in a gene governing molybdenum cofactor biosynthesis in Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 99:11-16. [PMID: 29803701 DOI: 10.1016/j.ibmb.2018.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/28/2018] [Accepted: 04/28/2018] [Indexed: 06/08/2023]
Abstract
Translucency of the larval integument in Bombyx mori is caused by a lack of uric acid in the epidermis. Hime'nichi translucent (ohi) is a unique mutation causing intermediate translucency of the larval integument and male-specific flaccid paralysis. To determine the gene associated with the ohi mutation, the ohi locus was mapped to a 400-kb region containing 29 predicted genes. Among the genes in this region, we focused on Bombyx homolog of mammalian Gephyrin (BmGphn), which regulates molybdenum cofactor (MoCo) biosynthesis, because MoCo is indispensable for the activity of xanthine dehydrogenase (XDH), a key enzyme in uric acid biosynthesis. The translucent integument of ohi larvae turned opaque after injection of bovine xanthine oxidase, which is a mammalian equivalent to XDH, indicating that XDH activity is defective in ohi larvae. RT-PCR and sequencing analysis showed that (i) in ohi larvae, expression of the BmGphn gene was repressed in the fat body where uric acid is synthesized, and (ii) there was no amino acid substitution in the ohi mutant allele. Finally, we obtained BmGphn knockout alleles (hereafter denoted as BmGphnΔ) by using CRISPR/Cas9. The resulting ohi/BmGphnΔ larvae had translucent integuments, demonstrating that BmGphn is the gene responsible for the ohi phenotype. Our results show that repressed expression of BmGphn is a causative factor for the defective MoCo biosynthesis and XDH activity observed in ohi larvae. Interestingly, all male BmGphnΔ homozygotes died before pupation and showed a flaccid paralysis phenotype. The genetic and physiological mechanisms underlying this flaccid paralysis phenotype are also discussed.
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Affiliation(s)
- Tsuguru Fujii
- Laboratory of Silkworm Genetic Resources, Institute of Genetic Resources, Graduate School of Bio Resources and Bioenvironmental Science, Kyushu University, Fukuoka, 812-8581, Japan
| | - Kazunori Yamamoto
- Laboratory of Silkworm Genetic Resources, Institute of Genetic Resources, Graduate School of Bio Resources and Bioenvironmental Science, Kyushu University, Fukuoka, 812-8581, Japan
| | - Yutaka Banno
- Laboratory of Silkworm Genetic Resources, Institute of Genetic Resources, Graduate School of Bio Resources and Bioenvironmental Science, Kyushu University, Fukuoka, 812-8581, Japan.
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8
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Zhang H, Kiuchi T, Hirayama C, Katsuma S, Shimada T. Bombyx ortholog of the Drosophila eye color gene brown controls riboflavin transport in Malpighian tubules. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 92:65-72. [PMID: 29191464 DOI: 10.1016/j.ibmb.2017.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/24/2017] [Accepted: 11/25/2017] [Indexed: 06/07/2023]
Abstract
The Drosophila eye color gene brown is known to control the transport of pteridine precursors in adult eyes. The Brown protein belongs to the ATP-binding cassette (ABC) transporter G family, which includes proteins encoded by the genes brown, scarlet, and white. These genes are responsible for pigmentation in Drosophila and the domestic silkworm Bombyx mori. Although orthologs of brown are conserved among insects, the function of this gene is only known in Drosophila. Here, we elucidated the function of the B. mori ortholog Bm-brown. We examined the spatial and temporal expression profiles of Bm-brown and found that this gene was specifically and continuously expressed in larval Malpighian tubules (MTs), indicating this gene has a special function in MTs. We then successfully obtained a Bm-brown knockout (KO) strain based on a wild-type (WT) strain using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9) system. We found that larval MTs of the KO strain were white, whereas those of WT were yellow. It is known that larval yellow MTs of WT are due to the accumulation of riboflavin. Therefore, we compared the riboflavin contents of MTs of KO and WT strains, and found that the riboflavin level in the KO strain was 20 fold less than that in WT during the 5th instar period. MTs are known to exhibit a similar milky color in w-3 mutant larvae due to a deficiency of riboflavin accumulation. The responsible gene for w-3 mutant is the Bmwh3 gene, which is orthologous to Drosophila white. Thus, we speculate that Bm-brown is heterodimerized with Bmwh3, similar to Brown/White in Drosophila, and acts as a riboflavin transporter in silkworm MTs.
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Affiliation(s)
- Haokun Zhang
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takashi Kiuchi
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Chikara Hirayama
- National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba City, Ibaraki 305-8634, Japan
| | - Susumu Katsuma
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toru Shimada
- 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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9
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Bm-muted , orthologous to mouse muted and encoding a subunit of the BLOC-1 complex, is responsible for the otm translucent mutation of the silkworm Bombyx mori. Gene 2017; 629:92-100. [DOI: 10.1016/j.gene.2017.07.071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 07/08/2017] [Accepted: 07/27/2017] [Indexed: 11/18/2022]
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10
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Fujii T, Yamamoto K, Banno Y. Molybdenum cofactor deficiency causes translucent integument, male-biased lethality, and flaccid paralysis in the silkworm Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 73:20-26. [PMID: 27041280 DOI: 10.1016/j.ibmb.2016.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/23/2016] [Accepted: 03/23/2016] [Indexed: 06/05/2023]
Abstract
Uric acid accumulates in the epidermis of Bombyx mori larvae and renders the larval integument opaque and white. Yamamoto translucent (oya) is a novel spontaneous mutant with a translucent larval integument and unique phenotypic characteristics, such as male-biased lethality and flaccid larval paralysis. Xanthine dehydrogenase (XDH) that requires a molybdenum cofactor (MoCo) for its activity is a key enzyme for uric acid synthesis. It has been observed that injection of a bovine xanthine oxidase, which corresponds functionally to XDH and contains its own MoCo activity, changes the integuments of oya mutants from translucent to opaque and white. This finding suggests that XDH/MoCo activity might be defective in oya mutants. Our linkage analysis identified an association between the oya locus and chromosome 23. Because XDH is not linked to chromosome 23 in B. mori, MoCo appears to be defective in oya mutants. In eukaryotes, MoCo is synthesized by a conserved biosynthesis pathway governed by four loci (MOCS1, MOCS2, MOCS3, and GEPH). Through a candidate gene approach followed by sequence analysis, a 6-bp deletion was detected in an exon of the B. mori molybdenum cofactor synthesis-step 1 gene (BmMOCS1) in the oya strain. Moreover, recombination was not observed between the oya and BmMOCS1 loci. These results indicate that the BmMOCS1 locus is responsible for the oya locus. Finally, we discuss the potential cause of male-biased lethality and flaccid paralysis observed in the oya mutants.
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Affiliation(s)
- Tsuguru Fujii
- Laboratory of Silkworm Genetic Resources, Institute of Genetic Resources, Graduate School of Bio Resources and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan
| | - Kimiko Yamamoto
- National Institute of Agrobiological Sciences, Tsukuba 305-8634, Japan
| | - Yutaka Banno
- Laboratory of Silkworm Genetic Resources, Institute of Genetic Resources, Graduate School of Bio Resources and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan.
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11
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Fukuda M. Multiple Roles of VARP in Endosomal Trafficking: Rabs, Retromer Components and R-SNARE VAMP7 Meet on VARP. Traffic 2016; 17:709-19. [PMID: 27103185 DOI: 10.1111/tra.12406] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 12/11/2022]
Abstract
VARP (VPS9-ankyrin-repeat protein, also known as ANKRD27) was originally identified as an N-terminal VPS9 (vacuolar protein sorting 9)-domain-containing protein that possesses guanine nucleotide exchange factor (GEF) activity toward small GTPase Rab21 and contains two ankyrin repeat (ANKR) domains in its central region. A number of VARP-interacting molecules have been identified during the past five years, and considerable attention is now being directed to the multiple roles of VARP in endosomal trafficking. More specifically, VARP is now known to interact with three different types of key membrane trafficking regulators, i.e. small GTPase Rabs (Rab32, Rab38 and Rab40C), the retromer complex (a sorting nexin dimer, VPS26, VPS29 and VPS35) and R-SNARE VAMP7. By binding to several of these molecules, VARP regulates endosomal trafficking, which underlies a variety of cellular events, including melanogenic enzyme trafficking to melanosomes, dendrite outgrowth of melanocytes, neurite outgrowth and retromer-mediated endosome-to-plasma membrane sorting of transmembrane proteins.
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Affiliation(s)
- Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
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Tabunoki H, Bono H, Ito K, Yokoyama T. Can the silkworm ( Bombyx mori) be used as a human disease model? Drug Discov Ther 2016; 10:3-8. [DOI: 10.5582/ddt.2016.01011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hiroko Tabunoki
- Department of Biological Production, Faculty of Agriculture, Tokyo university of Agriculture and Technology
| | - Hidemasa Bono
- Database Center for Life Science (DBCLS), Research Organization of Information and Systems (ROIS)
| | - Katsuhiko Ito
- Department of Biological Production, Faculty of Agriculture, Tokyo university of Agriculture and Technology
| | - Takeshi Yokoyama
- Department of Biological Production, Faculty of Agriculture, Tokyo university of Agriculture and Technology
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13
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Mapping and recombination analysis of two moth colour mutations, Black moth and Wild wing spot, in the silkworm Bombyx mori. Heredity (Edinb) 2015. [PMID: 26219230 DOI: 10.1038/hdy.2015.69] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Many lepidopteran insects exhibit body colour variations, where the high phenotypic diversity observed in the wings and bodies of adults provides opportunities for studying adaptive morphological evolution. In the silkworm Bombyx mori, two genes responsible for moth colour mutation, Bm and Ws, have been mapped to 0.0 and 14.7 cM of the B. mori genetic linkage group 17; however, these genes have not been identified at the molecular level. We performed positional cloning of both genes to elucidate the molecular mechanisms that underlie the moth wing- and body-colour patterns in B. mori. We successfully narrowed down Bm and Ws to ~2-Mb-long and 100-kb-long regions on the same scaffold Bm_scaf33. Gene prediction analysis of this region identified 77 candidate genes in the Bm region, whereas there were no candidate genes in the Ws region. Fluorescence in-situ hybridisation analysis in Bm mutant detected chromosome inversion, which explains why there are no recombination in the corresponding region. The comparative genomic analysis demonstrated that the candidate regions of both genes shared synteny with a region associated with wing- and body-colour variations in other lepidopteran species including Biston betularia and Heliconius butterflies. These results suggest that the genes responsible for wing and body colour in B. mori may be associated with similar genes in other Lepidoptera.
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14
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Wang L, Kiuchi T, Fujii T, Daimon T, Li M, Banno Y, Kikuta S, Kikawada T, Katsuma S, Shimada T. Mutation of a novel ABC transporter gene is responsible for the failure to incorporate uric acid in the epidermis of ok mutants of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:562-571. [PMID: 23567590 DOI: 10.1016/j.ibmb.2013.03.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/22/2013] [Accepted: 03/22/2013] [Indexed: 06/02/2023]
Abstract
ok mutants of the silkworm, Bombyx mori, exhibit highly translucent larval skin resulting from the inability to incorporate uric acid into the epidermal cells. Here we report the identification of a gene responsible for the ok mutation using positional cloning and RNAi experiments. In two independent ok mutant strains, we found a 49-bp deletion and a 233-bp duplication, respectively, in mRNAs of a novel gene, Bm-ok, which encodes a half-type ABC transporter, each of which results in translation of a truncated protein in each mutant. Although the Bm-ok sequence was homologous to well-known transporter genes, white, scarlet, and brown in Drosophila, the discovery of novel orthologs in the genomes of lepidopteran, hymenopteran, and hemipteran insects identifies it as a member of a new distinct subfamily of transporters. Embryonic RNAi of Bm-ok demonstrated that repression of Bm-ok causes a translucent phenotype in the first-instar silkworm larva. We discuss the possibility that Bm-ok forms a heterodimer with another half-type ABC transporter, Bmwh3, and acts as a uric acid transporter in the silkworm epidermis.
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Affiliation(s)
- Lingyan Wang
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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15
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Wang L, Kiuchi T, Fujii T, Daimon T, Li M, Banno Y, Katsuma S, Shimada T. Reduced expression of the dysbindin-like gene in the Bombyx mori ov mutant exhibiting mottled translucency of the larval skin. Genome 2013; 56:101-8. [DOI: 10.1139/gen-2012-0127] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ov (mottled translucent of Var) mutant, an oily mutant of Bombyx mori, exhibits mottled translucent skin with a varying degree of transparency among individuals. By linkage analysis of 2112 backcross individuals using polymorphic DNA markers, we successfully mapped a 179-kb region of chromosome 20 responsible for the ov phenotype. This region contains nine predicted genes. We compared the mRNA expression of these nine genes between the wild type and mutants and found that the expression of one of them, Bmdysb, was strikingly decreased in the epidermis of ov as well as its allelomorph, ovp. Moreover, its expression level was well correlated with the degree of transparency among individuals. Bmdysb was homologous to DTNBP1 encoding human dysbindin, a subunit of the biogenesis of lysosome-related organelles complex-1. Our results suggest that the translucent skin may be due to repression of Bmdysb in the ov mutants and that Bmdysb plays an important role in the formation and accumulation of urate granules in the silkworm epidermis.
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Affiliation(s)
- Lingyan Wang
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
| | - Takashi Kiuchi
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
| | - Tsuguru Fujii
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
| | - Takaaki Daimon
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
| | - Muwang Li
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
| | - Yutaka Banno
- Institute of Genetic Resources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Hakozaki, Fukuoka, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
| | - Toru Shimada
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan
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Fujii T, Banno Y, Abe H, Katsuma S, Shimada T. A homolog of the human Hermansky–Pudluck syndrome-5 (HPS5) gene is responsible for the oa larval translucent mutants in the silkworm, Bombyx mori. Genetica 2012; 140:463-8. [DOI: 10.1007/s10709-012-9694-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 12/03/2012] [Indexed: 10/27/2022]
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17
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Ito K, Kidokoro K, Katsuma S, Shimada T, Yamamoto K, Mita K, Kadono-Okuda K. Positional cloning of a gene responsible for the cts mutation of the silkworm, Bombyx mori. Genome 2012; 55:493-504. [DOI: 10.1139/g2012-033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The larval head cuticle and anal plates of the silkworm mutant cheek and tail spot (cts) have chocolate-colored spots, unlike the entirely white appearance of the wild-type (WT) strain. We report the identification and characterization of the gene responsible for the cts mutation. Positional cloning revealed a cts candidate on chromosome 16, designated BmMFS, based on the high similarity of the deduced amino acid sequence between the candidate gene from the WT strain and the major facilitator superfamily (MFS) protein. BmMFS likely encodes a membrane protein with 11 putative transmembrane domains, while the putative structure deduced from the cts-type allele possesses only 10-pass transmembrane domains owing to a deletion in its coding region. Quantitative RT–PCR analysis showed that BmMFS mRNA was strongly expressed in the integument of the head and tail, where the cts phenotype is observed; expression markedly increased at the molting and newly ecdysed stages. These results indicate that the novel BmMFS gene is cts and the membrane structure of its protein accounts for the cts phenotype. These expression profiles and the cts phenotype are quite similar to those of melanin-related genes, such as Bmyellow-e and Bm-iAANAT, suggesting that BmMFS is involved in the melanin synthesis pathway.
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Affiliation(s)
- Katsuhiko Ito
- Insect Genome Research Unit, Agrogenonmics Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Kurako Kidokoro
- Insect Genome Research Unit, Agrogenonmics Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, 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
| | - 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
| | - Kimiko Yamamoto
- Insect Genome Research Unit, Agrogenonmics Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Kazuei Mita
- Insect Genome Research Unit, Agrogenonmics Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Keiko Kadono-Okuda
- Insect Genome Research Unit, Agrogenonmics Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan
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18
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Kiuchi T, Banno Y, Katsuma S, Shimada T. Mutations in an amino acid transporter gene are responsible for sex-linked translucent larval skin of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:680-687. [PMID: 21619931 DOI: 10.1016/j.ibmb.2011.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 04/20/2011] [Accepted: 04/27/2011] [Indexed: 05/30/2023]
Abstract
The sex-linked translucent (os) mutation in the silkworm, Bombyx mori, confers slightly translucent larval skin resulting from a decrease in the incorporation of uric acid into epidermal cells. By positional cloning, we narrowed a region linked to the os phenotype to approximately 157 kb located on scaffold Bm_scaf72 on the Z chromosome (chromosome 1). The region contained four gene models. Sequencing analysis revealed that one of the candidate genes had a 7-bp deletion in the coding region. We also found a 111-bp deletion or single-nucleotide substitution in the same gene using independent os mutant strains. Because all the mutations caused the generation of abnormal transcripts followed by translation of a truncated protein, we conclude that the mutation of this candidate gene is responsible for the translucent larval skin of the os mutant. Sequence analysis indicated that the gene responsible for the os mutation had homology to amino acid transporters of the solute carrier family of proteins. Our results suggest that solute carrier proteins are involved in uric acid transport in insects and other invertebrates.
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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, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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19
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Zhan S, Guo Q, Li M, Li M, Li J, Miao X, Huang Y. Disruption of an N-acetyltransferase gene in the silkworm reveals a novel role in pigmentation. Development 2010; 137:4083-90. [DOI: 10.1242/dev.053678] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pigmentation of insects has served as an excellent model for the study of morphological trait evolution and developmental biology. The melanism (mln) mutant of the silkworm Bombyx mori is notable for its strong black coloration, phenotypic differences between larval and adult stages, and its widespread use in strain selection. Here, we report the genetic and molecular bases for the formation of the mln morphological trait. Fine mapping revealed that an arylalkylamine N-acetyltransferase (AANAT) gene co-segregates with the black coloration patterns. Coding sequence variations and expression profiles of AANAT are also associated with the melanic phenotypes. A 126 bp deletion in the mln genome causes two alternatively spliced transcripts with premature terminations. An enzymatic assay demonstrated the absolute loss of AANAT activity in the mutant proteins. We also performed RNA interference of AANAT in wild-type pupae and observed a significant proportion of adults with ectopic black coloration. These findings indicate that functional deletion of this AANAT gene accounts for the mln mutation in silkworm. AANAT is also involved in a parallel melanin synthesis pathway in which ebony plays a role, whereas no pigmentation defect has been reported in the Drosophila model or in other insects to date. To the best of our knowledge, the mln mutation is the first characterized mutant phenotype of insects with AANAT, and this result contributes to our understanding of dopamine metabolism and melanin pattern polymorphisms.
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Affiliation(s)
- Shuai Zhan
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- The Graduate School, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Qiuhong Guo
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Minghui Li
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Muwang Li
- Sericultural Research Institute, Chinese Academy of Agriculture Sciences, Zhenjiang, 212018, China
| | - Jianyong Li
- Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Xuexia Miao
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yongping Huang
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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Fujii T, Daimon T, Uchino K, Banno Y, Katsuma S, Sezutsu H, Tamura T, Shimada T. Transgenic analysis of the BmBLOS2 gene that governs the translucency of the larval integument of the silkworm, Bombyx mori. INSECT MOLECULAR BIOLOGY 2010; 19:659-667. [PMID: 20546041 DOI: 10.1111/j.1365-2583.2010.01020.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The larval integument of the silkworm, Bombyx mori, is opaque because urate granules accumulate in the epidermis. Although the biosynthetic pathway of uric acid is well studied, little is known about how uric acid accumulates as urate granules in epidermal cells. In the distinct oily (od) mutant silkworm, the larval integument is translucent because of the inability to construct urate granules. Recently, we have found that the od mutant has a genomic deletion in the B. mori homologue of the human biogenesis of lysosome-related organelles complex1, subunit 2 (BLOS2) gene (BmBLOS2). Here, we performed a molecular and functional characterization of BmBLOS2. Northern blot analysis showed that BmBLOS2 was ubiquitously expressed in various tissues. We analysed the structure of a newly isolated mutant (od(B) ) allelic to od and found a premature stop codon in the coding sequence of BmBLOS2 in this new mutation. Moreover, the translucent phenotype was rescued by the germ-line transformation of the wild-type BmBLOS2 allele into the od mutant. Our results suggest that BmBLOS2 is responsible for the od mutant phenotype and plays a crucial role in biogenesis of urate granules in the larval epidermis of the silkworm. The relationships amongst Hermansky-Pudlak syndrome (HPS) genes in mammals, granule group genes in Drosophila and translucent mutant genes in B. mori are discussed.
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Affiliation(s)
- T Fujii
- 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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21
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Niwa R, Namiki T, Ito K, Shimada-Niwa Y, Kiuchi M, Kawaoka S, Kayukawa T, Banno Y, Fujimoto Y, Shigenobu S, Kobayashi S, Shimada T, Katsuma S, Shinoda T. Non-molting glossy/shroud encodes a short-chain dehydrogenase/reductase that functions in the 'Black Box' of the ecdysteroid biosynthesis pathway. Development 2010; 137:1991-9. [PMID: 20501590 DOI: 10.1242/dev.045641] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In insects, the precise timing of molting and metamorphosis is strictly guided by a principal steroid hormone, ecdysone. Among the multiple conversion steps for synthesizing ecdysone from dietary cholesterol, the conversion of 7-dehydrocholesterol to 5beta-ketodiol, the so-called 'Black Box', is thought to be the important rate-limiting step. Although a number of genes essential for ecdysone synthesis have recently been revealed, much less is known about the genes that are crucial for functioning in the Black Box. Here we report on a novel ecdysteroidgenic gene, non-molting glossy (nm-g)/shroud (sro), which encodes a short-chain dehydrogenase/reductase. This gene was first isolated by positional cloning of the nm-g mutant of the silkworm Bombyx mori, which exhibits a low ecdysteroid titer and consequently causes a larval arrest phenotype. In the fruit fly, Drosophila melanogaster, the closest gene to nm-g is encoded by the sro locus, one of the Halloween mutant members that are characterized by embryonic ecdysone deficiency. The lethality of the sro mutant is rescued by the overexpression of either sro or nm-g genes, indicating that these two genes are orthologous. Both the nm-g and the sro genes are predominantly expressed in tissues producing ecdysone, such as the prothoracic glands and the ovaries. Furthermore, the phenotypes caused by the loss of function of these genes are restored by the application of ecdysteroids and their precursor 5beta-ketodiol, but not by cholesterol or 7-dehydrocholesterol. Altogether, we conclude that the Nm-g/Sro family protein is an essential enzyme for ecdysteroidogenesis working in the Black Box.
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Affiliation(s)
- Ryusuke Niwa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan.
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22
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Futahashi R, Banno Y, Fujiwara H. Caterpillar color patterns are determined by a two-phase melanin gene prepatterning process: new evidence from tan and laccase2. Evol Dev 2010; 12:157-67. [PMID: 20433456 DOI: 10.1111/j.1525-142x.2010.00401.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ryo Futahashi
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan
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Ito K, Katsuma S, Yamamoto K, Kadono-Okuda K, Mita K, Shimada T. Yellow-e determines the color pattern of larval head and tail spots of the silkworm Bombyx mori. J Biol Chem 2009; 285:5624-9. [PMID: 19996320 DOI: 10.1074/jbc.m109.035741] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Yellow proteins form a large family in insects. In Drosophila melanogaster, there are 14 yellow genes in the genome. Previous studies have shown that the yellow gene is necessary for normal pigmentation; however, the roles of other yellow genes in body coloration are not known. Here, we provide the first evidence that yellow-e is required for normal body color pattern in insect larvae. In two mutant strains, bts and its allele bts2, of the silkworm Bombyx mori, the larval head cuticle and anal plates are reddish brown instead of the white color found in the wild type. Positional cloning revealed that deletions in the Bombyx homolog of the Drosophila yellow-e gene (Bmyellow-e) were responsible for the bts/bts2 phenotype. Bmyellow-e mRNA was strongly expressed in the trachea, testis, and integument, and expression markedly increased at the molting stages. This profile is quite similar to that of Bmyellow, a regulator of neonatal body color and body markings in Bombyx. Quantitative reverse transcription-PCR analysis showed that Bmyellow-e mRNA was heavily expressed in the integument of the head and tail in which the bts phenotype is observed. The present results suggest that Yellow-e plays a crucial role in the pigmentation process of lepidopteran larvae.
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Affiliation(s)
- Katsuhiko Ito
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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