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Zhang L, Zhang K, Yang F, Dayananda B, Cao Y, Hu Z, Liu Y. Chromosome-level genome of Scolopendra mutilans provides insights into its evolution. Integr Zool 2024. [PMID: 39075924 DOI: 10.1111/1749-4877.12871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Report the first chromosome level genome of myriapod Scolopendra mutilans. Reveal gene expansions for importance to adapt. Annotate nine Hox cluster genes in this genome.
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Affiliation(s)
- Lin Zhang
- Hubei Shizhen Laboratory, Hubei Key Laboratory of Theory and Application Research of Liver and Kidney in Traditional Chinese Medicine, School of Basic Medical Sciences, Hubei University of Chinese Medicine, Wuhan, China
| | - Kai Zhang
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Fang Yang
- School of Laboratory Medicine, Hubei University of Chinese Medicine, Wuhan, China
| | - Buddhi Dayananda
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Yunpeng Cao
- Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Zhigang Hu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
| | - Yifei Liu
- College of Pharmacy, Hubei University of Chinese Medicine, Wuhan, China
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2
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Hemba-Waduge RUS, Liu M, Li X, Sun JL, Budslick EA, Bondos SE, Ji JY. Metabolic control by the Bithorax Complex-Wnt signaling crosstalk in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596851. [PMID: 38853890 PMCID: PMC11160800 DOI: 10.1101/2024.05.31.596851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Adipocytes distributed throughout the body play crucial roles in lipid metabolism and energy homeostasis. Regional differences among adipocytes influence normal function and disease susceptibility, but the mechanisms driving this regional heterogeneity remain poorly understood. Here, we report a genetic crosstalk between the Bithorax Complex ( BX-C ) genes and Wnt/Wingless signaling that orchestrates regional differences among adipocytes in Drosophila larvae. Abdominal adipocytes, characterized by the exclusive expression of abdominal A ( abd-A ) and Abdominal B ( Abd-B ), exhibit distinct features compared to thoracic adipocytes, with Wnt signaling further amplifying these disparities. Depletion of BX-C genes in adipocytes reduces fat accumulation, delays larval-pupal transition, and eventually leads to pupal lethality. Depleting Abd-A or Abd-B reduces Wnt target gene expression, thereby attenuating Wnt signaling-induced lipid mobilization. Conversely, Wnt signaling stimulated abd-A transcription, suggesting a feedforward loop that amplifies the interplay between Wnt signaling and BX-C in adipocytes. These findings elucidate how the crosstalk between cell-autonomous BX-C gene expression and Wnt signaling define unique metabolic behaviors in adipocytes in different anatomical regions of fat body, delineating larval adipose tissue domains.
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3
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Fu X, Zhu X. Key homeobox transcription factors regulate the development of the firefly's adult light organ and bioluminescence. Nat Commun 2024; 15:1736. [PMID: 38443352 PMCID: PMC10914744 DOI: 10.1038/s41467-024-45559-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 01/26/2024] [Indexed: 03/07/2024] Open
Abstract
Adult fireflies exhibit unique flashing courtship signals, emitted by specialized light organs, which develop mostly independently from larval light organs during the pupal stage. The mechanisms of adult light organ development have not been thoroughly studied until now. Here we show that key homeobox transcription factors AlABD-B and AlUNC-4 regulate the development of adult light organs and bioluminescence in the firefly Aquatica leii. Interference with the expression of AlAbd-B and AlUnc-4 genes results in undeveloped or non-luminescent adult light organs. AlABD-B regulates AlUnc-4, and they interact with each other. AlABD-B and AlUNC-4 activate the expression of the luciferase gene AlLuc1 and some peroxins. Four peroxins are involved in the import of AlLUC1 into peroxisomes. Our study provides key insights into the development of adult light organs and flash signal control in fireflies.
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Affiliation(s)
- Xinhua Fu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Xinlei Zhu
- Firefly Conservation Research Centre, Wuhan, 430070, China
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4
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Liu J, Fan H, Liang X, Chen Y. Polycomb repressor complex: Its function in human cancer and therapeutic target strategy. Biomed Pharmacother 2023; 169:115897. [PMID: 37981459 DOI: 10.1016/j.biopha.2023.115897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
The Polycomb Repressor Complex (PRC) plays a pivotal role in gene regulation during development and disease, with dysregulation contributing significantly to various human cancers. The intricate interplay between PRC and cellular signaling pathways sheds light on cancer complexity. PRC presents promising therapeutic opportunities, with inhibitors undergoing rigorous evaluation in preclinical and clinical studies. In this review, we emphasize the critical role of PRC complex in gene regulation, particularly PcG proteins mediated chromatin compaction through phase separation. We also highlight the pathological implications of PRC complex dysregulation in various tumors, elucidating underlying mechanisms driving cancer progression. The burgeoning field of therapeutic strategies targeting PRC complexes, notably EZH2 inhibitors, has advanced significantly. However, we explore the need for combination therapies to enhance PRC targeted treatments efficacy, providing a glimpse into the future of cancer therapeutics.
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Affiliation(s)
- Jingrong Liu
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Hongjie Fan
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Xinmiao Liang
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Yang Chen
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
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5
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Ibragimov A, Bing XY, Shidlovskii YV, Levine M, Georgiev P, Schedl P. lncRNA read-through regulates the BX-C insulator Fub-1. eLife 2023; 12:e84711. [PMID: 37643473 PMCID: PMC10497285 DOI: 10.7554/elife.84711] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 08/09/2023] [Indexed: 08/31/2023] Open
Abstract
Though long non-coding RNAs (lncRNAs) represent a substantial fraction of the Pol II transcripts in multicellular animals, only a few have known functions. Here we report that the blocking activity of the Bithorax complex (BX-C) Fub-1 boundary is segmentally regulated by its own lncRNA. The Fub-1 boundary is located between the Ultrabithorax (Ubx) gene and the bxd/pbx regulatory domain, which is responsible for regulating Ubx expression in parasegment PS6/segment A1. Fub-1 consists of two hypersensitive sites, HS1 and HS2. HS1 is an insulator while HS2 functions primarily as an lncRNA promoter. To activate Ubx expression in PS6/A1, enhancers in the bxd/pbx domain must be able to bypass Fub-1 blocking activity. We show that the expression of the Fub-1 lncRNAs in PS6/A1 from the HS2 promoter inactivates Fub-1 insulating activity. Inactivation is due to read-through as the HS2 promoter must be directed toward HS1 to disrupt blocking.
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Affiliation(s)
- Airat Ibragimov
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of SciencesMoscowRussian Federation
| | - Xin Yang Bing
- Lewis Sigler Institute, Princeton UniversityPrincetonUnited States
| | - Yulii V Shidlovskii
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of SciencesMoscowRussian Federation
- Department of Biology and General Genetics, Sechenov UniversityMoscowRussian Federation
| | - Michael Levine
- Lewis Sigler Institute, Princeton UniversityPrincetonUnited States
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of SciencesMoscowRussian Federation
| | - Paul Schedl
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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6
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Kyrchanova O, Sokolov V, Tikhonov M, Manukyan G, Schedl P, Georgiev P. Transcriptional Readthrough Interrupts Boundary Function in Drosophila. Int J Mol Sci 2023; 24:11368. [PMID: 37511131 PMCID: PMC10379149 DOI: 10.3390/ijms241411368] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
In higher eukaryotes, distance enhancer-promoter interactions are organized by topologically associated domains, tethering elements, and chromatin insulators/boundaries. While insulators/boundaries play a central role in chromosome organization, the mechanisms regulating their functions are largely unknown. In the studies reported here, we have taken advantage of the well-characterized Drosophila bithorax complex (BX-C) to study one potential mechanism for controlling boundary function. The regulatory domains of BX-C are flanked by boundaries, which block crosstalk with their neighboring domains and also support long-distance interactions between the regulatory domains and their target gene. As many lncRNAs have been found in BX-C, we asked whether readthrough transcription (RT) can impact boundary function. For this purpose, we took advantage of two BX-C boundary replacement platforms, Fab-7attP50 and F2attP, in which the Fab-7 and Fub boundaries, respectively, are deleted and replaced with an attP site. We introduced boundary elements, promoters, and polyadenylation signals arranged in different combinations and then assayed for boundary function. Our results show that RT can interfere with boundary activity. Since lncRNAs represent a significant fraction of Pol II transcripts in multicellular eukaryotes, it is therefore possible that RT may be a widely used mechanism to alter boundary function and regulation of gene expression.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Vladimir Sokolov
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Maxim Tikhonov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Galya Manukyan
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
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7
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Phanindhar K, Mishra RK. Auxin-inducible degron system: an efficient protein degradation tool to study protein function. Biotechniques 2023; 74:186-198. [PMID: 37191015 DOI: 10.2144/btn-2022-0108] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
Targeted protein degradation, with its rapid protein depletion kinetics, allows the measurement of acute changes in the cell. The auxin-inducible degron (AID) system, rapidly degrades AID-tagged proteins only in the presence of auxin. The AID system being inducible makes the study of essential genes and dynamic processes like cell differentiation, cell cycle and genome organization feasible. The AID degradation system has been adapted to yeast, protozoans, C. elegans, Drosophila, zebrafish, mouse and mammalian cell lines. Using the AID system, researchers have unveiled novel functions for essential proteins at developmental stages that were previously difficult to investigate due to early lethality. This comprehensive review discusses the development, advancements, applications and drawbacks of the AID system and compares it with other available protein degradation systems.
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Affiliation(s)
- Kundurthi Phanindhar
- CSIR-Centre for Cellular & Molecular Biology (CCMB), Uppal Road, Hyderabad, 500007, India
| | - Rakesh K Mishra
- CSIR-Centre for Cellular & Molecular Biology (CCMB), Uppal Road, Hyderabad, 500007, India
- Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, 201002, India
- Tata Institute for Genetics & Society (TIGS), Bangalore, 560065, India
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8
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Quesnelle DC, Bendena WG, Chin-Sang ID. A Compilation of the Diverse miRNA Functions in Caenorhabditis elegans and Drosophila melanogaster Development. Int J Mol Sci 2023; 24:ijms24086963. [PMID: 37108126 PMCID: PMC10139094 DOI: 10.3390/ijms24086963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
MicroRNAs are critical regulators of post-transcriptional gene expression in a wide range of taxa, including invertebrates, mammals, and plants. Since their discovery in the nematode, Caenorhabditis elegans, miRNA research has exploded, and they are being identified in almost every facet of development. Invertebrate model organisms, particularly C. elegans, and Drosophila melanogaster, are ideal systems for studying miRNA function, and the roles of many miRNAs are known in these animals. In this review, we compiled the functions of many of the miRNAs that are involved in the development of these invertebrate model species. We examine how gene regulation by miRNAs shapes both embryonic and larval development and show that, although many different aspects of development are regulated, several trends are apparent in the nature of their regulation.
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Affiliation(s)
| | - William G Bendena
- Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Ian D Chin-Sang
- Department of Biology, Queen's University, Kingston, ON K7L 3N6, Canada
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9
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Salzler HR, Vandadi V, McMichael BD, Brown JC, Boerma SA, Leatham-Jensen MP, Adams KM, Meers MP, Simon JM, Duronio RJ, McKay DJ, Matera AG. Distinct roles for canonical and variant histone H3 lysine-36 in Polycomb silencing. SCIENCE ADVANCES 2023; 9:eadf2451. [PMID: 36857457 PMCID: PMC9977188 DOI: 10.1126/sciadv.adf2451] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 01/31/2023] [Indexed: 05/26/2023]
Abstract
Polycomb complexes regulate cell type-specific gene expression programs through heritable silencing of target genes. Trimethylation of histone H3 lysine 27 (H3K27me3) is essential for this process. Perturbation of H3K36 is thought to interfere with H3K27me3. We show that mutants of Drosophila replication-dependent (H3.2K36R) or replication-independent (H3.3K36R) histone H3 genes generally maintain Polycomb silencing and reach later stages of development. In contrast, combined (H3.3K36RH3.2K36R) mutants display widespread Hox gene misexpression and fail to develop past the first larval stage. Chromatin profiling revealed that the H3.2K36R mutation disrupts H3K27me3 levels broadly throughout silenced domains, whereas these regions are mostly unaffected in H3.3K36R animals. Analysis of H3.3 distributions showed that this histone is enriched at presumptive Polycomb response elements located outside of silenced domains but relatively depleted from those inside. We conclude that H3.2 and H3.3 K36 residues collaborate to repress Hox genes using different mechanisms.
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Affiliation(s)
- Harmony R. Salzler
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Vasudha Vandadi
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Benjamin D. McMichael
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - John C. Brown
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Sally A. Boerma
- Department of Biology, Carleton College, Northfield, MN, USA
| | - Mary P. Leatham-Jensen
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Kirsten M. Adams
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Michael P. Meers
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Jeremy M. Simon
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| | - Robert J. Duronio
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| | - Daniel J. McKay
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
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10
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Kyrchanova O, Sokolov V, Tikhonov M, Schedl P, Georgiev P. Transcriptional read through interrupts boundary function in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528790. [PMID: 36824960 PMCID: PMC9949125 DOI: 10.1101/2023.02.16.528790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
In higher eukaryotes enhancer-promoter interactions are known to be restricted by the chromatin insulators/boundaries that delimit topologically associated domains (TADs); however, there are instances in which enhancer-promoter interactions span one or more boundary elements/TADs. At present, the mechanisms that enable cross-TAD regulatory interaction are not known. In the studies reported here we have taken advantage of the well characterized Drosophila Bithorax complex (BX-C) to study one potential mechanism for controlling boundary function and TAD organization. The regulatory domains of BX-C are flanked by boundaries which function to block crosstalk with their neighboring domains and also to support long distance interactions between the regulatory domains and their target gene. As many lncRNAs have been found in BX-C, we asked whether transcriptional readthrough can impact boundary function. For this purpose, we took advantage of two BX-C boundary replacement platforms, Fab-7 attP50 and F2 attP , in which the Fab-7 and Fub boundaries, respectively, are deleted and replaced with an attP site. We introduced boundary elements, promoters and polyadenylation signals arranged in different combinations and then assayed for boundary function. Our results show that transcriptional readthrough can interfere with boundary activity. Since lncRNAs represent a significant fraction of Pol II transcripts in multicellular eukaryotes, it is possible that many of them may function in the regulation of TAD organization. Author Summary Recent studies have shown that much genome in higher eukaryotes is transcribed into non-protein coding lncRNAs. It is though that lncRNAs may preform important regulatory functions, including the formation of protein complexes, organization of functional interactions between enhancers and promoters and the maintenance of open chromatin. Here we examined how transcription from promoters inserted into the Drosophila Bithorax complex can impact the boundaries that are responsible for establishing independent regulatory domains. Surprisingly, we found that even a relatively low level of transcriptional readthrough can impair boundary function. Transcription also affects the activity of enhancers located in BX-C regulatory domains. Taken together, our results raise the possibility that transcriptional readthrough may be a widely used mechanism to alter chromosome structure and regulate gene expression.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia,Corresponding author: (PG), (PS)
| | - Vladimir Sokolov
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Maxim Tikhonov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA,Corresponding author: (PG), (PS)
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia,Corresponding author: (PG), (PS)
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11
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Buffry AD, Kittelmann S, McGregor AP. Characterisation of the role and regulation of Ultrabithorax in sculpting fine-scale leg morphology. Front Cell Dev Biol 2023; 11:1119221. [PMID: 36861038 PMCID: PMC9968978 DOI: 10.3389/fcell.2023.1119221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 01/20/2023] [Indexed: 02/16/2023] Open
Abstract
Hox genes are expressed during embryogenesis and determine the regional identity of animal bodies along the antero-posterior axis. However, they also function post-embryonically to sculpt fine-scale morphology. To better understand how Hox genes are integrated into post-embryonic gene regulatory networks, we further analysed the role and regulation of Ultrabithorax (Ubx) during leg development in Drosophila melanogaster. Ubx regulates several aspects of bristle and trichome patterning on the femurs of the second (T2) and third (T3) leg pairs. We found that repression of trichomes in the proximal posterior region of the T2 femur by Ubx is likely mediated by activation of the expression of microRNA-92a and microRNA-92b by this Hox protein. Furthermore, we identified a novel enhancer of Ubx that recapitulates the temporal and regional activity of this gene in T2 and T3 legs. We then used transcription factor (TF) binding motif analysis in regions of accessible chromatin in T2 leg cells to predict and functionally test TFs that may regulate the Ubx leg enhancer. We also tested the role of the Ubx co-factors Homothorax (Hth) and Extradenticle (Exd) in T2 and T3 femurs. We found several TFs that may act upstream or in concert with Ubx to modulate trichome patterning along the proximo-distal axis of developing femurs and that the repression of trichomes also requires Hth and Exd. Taken together our results provide insights into how Ubx is integrated into a post-embryonic gene regulatory network to determine fine-scale leg morphology.
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Affiliation(s)
- Alexandra D. Buffry
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Sebastian Kittelmann
- Centre for Functional Genomics, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Alistair P. McGregor
- Department of Biosciences, Durham University, Durham, United Kingdom,*Correspondence: Alistair P. McGregor,
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12
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Kahn TG, Savitsky M, Kuong C, Jacquier C, Cavalli G, Chang JM, Schwartz YB. Topological screen identifies hundreds of Cp190- and CTCF-dependent Drosophila chromatin insulator elements. SCIENCE ADVANCES 2023; 9:eade0090. [PMID: 36735780 PMCID: PMC9897668 DOI: 10.1126/sciadv.ade0090] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
Drosophila insulators were the first DNA elements found to regulate gene expression by delimiting chromatin contacts. We still do not know how many of them exist and what impact they have on the Drosophila genome folding. Contrary to vertebrates, there is no evidence that fly insulators block cohesin-mediated chromatin loop extrusion. Therefore, their mechanism of action remains uncertain. To bridge these gaps, we mapped chromatin contacts in Drosophila cells lacking the key insulator proteins CTCF and Cp190. With this approach, we found hundreds of insulator elements. Their study indicates that Drosophila insulators play a minor role in the overall genome folding but affect chromatin contacts locally at many loci. Our observations argue that Cp190 promotes cobinding of other insulator proteins and that the model, where Drosophila insulators block chromatin contacts by forming loops, needs revision. Our insulator catalog provides an important resource to study mechanisms of genome folding.
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Affiliation(s)
- Tatyana G. Kahn
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - Chikuan Kuong
- Department of Computer Science, National Chengchi University, Taipei City, Taiwan
| | | | - Giacomo Cavalli
- Institute of Human Genetics, UMR9002 CNRS, Montpellier, France
| | - Jia-Ming Chang
- Department of Computer Science, National Chengchi University, Taipei City, Taiwan
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13
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Mechanisms of Interaction between Enhancers and Promoters in Three Drosophila Model Systems. Int J Mol Sci 2023; 24:ijms24032855. [PMID: 36769179 PMCID: PMC9917889 DOI: 10.3390/ijms24032855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
In higher eukaryotes, the regulation of developmental gene expression is determined by enhancers, which are often located at a large distance from the promoters they regulate. Therefore, the architecture of chromosomes and the mechanisms that determine the functional interaction between enhancers and promoters are of decisive importance in the development of organisms. Mammals and the model animal Drosophila have homologous key architectural proteins and similar mechanisms in the organization of chromosome architecture. This review describes the current progress in understanding the mechanisms of the formation and regulation of long-range interactions between enhancers and promoters at three well-studied key regulatory loci in Drosophila.
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14
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Hajirnis N, Pandey S, Mishra RK. CRISPR/Cas9 and FLP-FRT mediated regulatory dissection of the BX-C of Drosophila melanogaster. CHROMOSOME RESEARCH : AN INTERNATIONAL JOURNAL ON THE MOLECULAR, SUPRAMOLECULAR AND EVOLUTIONARY ASPECTS OF CHROMOSOME BIOLOGY 2023; 31:7. [PMID: 36719476 DOI: 10.1007/s10577-023-09716-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 02/01/2023]
Abstract
The homeotic genes or Hox define the anterior-posterior (AP) body axis formation in bilaterians and are often present on the chromosome in an order collinear to their function across the AP axis. However, there are many cases wherein the Hox are not collinear, but their expression pattern is conserved across the AP axis. The expression pattern of Hox is attributed to the cis-regulatory modules (CRMs) consisting of enhancers, initiators, or repressor elements that regulate the genes in a segment-specific manner. In the Drosophila melanogaster Hox complex, the bithorax complex (BX-C) and even the CRMs are organized in an order that is collinear to their function in the thoracic and abdominal segments. In the present study, the regulatorily inert regions were targeted using CRISPR/Cas9 to generate a series of transgenic lines with the insertion of FRT sequences. These FRT lines are repurposed to shuffle the CRMs associated with Abd-B to generate modular deletion, duplication, or inversion of multiple CRMs. The rearrangements yielded entirely novel phenotypes in the fly suggesting the requirement of such complex manipulations to address the significance of higher order arrangement of the CRMs. The functional map and the transgenic flies generated in this study are important resources to decipher the collective ability of multiple regulatory elements in the eukaryotic genome to function as complex modules.
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Affiliation(s)
- Nikhil Hajirnis
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad, India.,Department of Anatomy and Neurobiology, University of Maryland, Baltimore, USA
| | | | - Rakesh K Mishra
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad, India. .,AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India. .,Tata Institute for Genetics and Society (TIGS), Bangalore, India.
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15
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Recent Advances and Future Potential of Long Non-Coding RNAs in Insects. Int J Mol Sci 2023; 24:ijms24032605. [PMID: 36768922 PMCID: PMC9917219 DOI: 10.3390/ijms24032605] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 01/31/2023] Open
Abstract
Over the last decade, long non-coding RNAs (lncRNAs) have witnessed a steep rise in interest amongst the scientific community. Because of their functional significance in several biological processes, i.e., alternative splicing, epigenetics, cell cycle, dosage compensation, and gene expression regulation, lncRNAs have transformed our understanding of RNA's regulatory potential. However, most knowledge concerning lncRNAs comes from mammals, and our understanding of the potential role of lncRNAs amongst insects remains unclear. Technological advances such as RNA-seq have enabled entomologists to profile several hundred lncRNAs in insect species, although few are functionally studied. This article will review experimentally validated lncRNAs from different insects and the lncRNAs identified via bioinformatic tools. Lastly, we will discuss the existing research challenges and the future of lncRNAs in insects.
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16
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Gaunt SJ. Seeking Sense in the Hox Gene Cluster. J Dev Biol 2022; 10:jdb10040048. [PMID: 36412642 PMCID: PMC9680502 DOI: 10.3390/jdb10040048] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/31/2022] [Accepted: 11/09/2022] [Indexed: 11/18/2022] Open
Abstract
The Hox gene cluster, responsible for patterning of the head-tail axis, is an ancestral feature of all bilaterally symmetrical animals (the Bilateria) that remains intact in a wide range of species. We can say that the Hox cluster evolved successfully only once since it is commonly the same in all groups, with labial-like genes at one end of the cluster expressed in the anterior embryo, and Abd-B-like genes at the other end of the cluster expressed posteriorly. This review attempts to make sense of the Hox gene cluster and to address the following questions. How did the Hox cluster form in the protostome-deuterostome last common ancestor, and why was this with a particular head-tail polarity? Why is gene clustering usually maintained? Why is there collinearity between the order of genes along the cluster and the positions of their expressions along the embryo? Why do the Hox gene expression domains overlap along the embryo? Why have vertebrates duplicated the Hox cluster? Why do Hox gene knockouts typically result in anterior homeotic transformations? How do animals adapt their Hox clusters to evolve new structural patterns along the head-tail axis?
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Affiliation(s)
- Stephen J Gaunt
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
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17
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Singh NP, Krumlauf R. Diversification and Functional Evolution of HOX Proteins. Front Cell Dev Biol 2022; 10:798812. [PMID: 35646905 PMCID: PMC9136108 DOI: 10.3389/fcell.2022.798812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/08/2022] [Indexed: 01/07/2023] Open
Abstract
Gene duplication and divergence is a major contributor to the generation of morphological diversity and the emergence of novel features in vertebrates during evolution. The availability of sequenced genomes has facilitated our understanding of the evolution of genes and regulatory elements. However, progress in understanding conservation and divergence in the function of proteins has been slow and mainly assessed by comparing protein sequences in combination with in vitro analyses. These approaches help to classify proteins into different families and sub-families, such as distinct types of transcription factors, but how protein function varies within a gene family is less well understood. Some studies have explored the functional evolution of closely related proteins and important insights have begun to emerge. In this review, we will provide a general overview of gene duplication and functional divergence and then focus on the functional evolution of HOX proteins to illustrate evolutionary changes underlying diversification and their role in animal evolution.
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Affiliation(s)
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, United States
- Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS, United States
- *Correspondence: Robb Krumlauf,
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18
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Kyrchanova OV, Postika NY, Sokolov VV, Georgiev PG. Fragments of the Fab-3 and Fab-4 Boundaries of the Drosophila melanogaster Bithorax Complex That Include CTCF Sites Are not Effective Insulators. DOKL BIOCHEM BIOPHYS 2022; 502:21-24. [PMID: 35275301 PMCID: PMC8917101 DOI: 10.1134/s1607672922010069] [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: 09/17/2021] [Revised: 10/01/2021] [Accepted: 10/03/2021] [Indexed: 11/22/2022]
Abstract
The segment-specific regulatory domains of the Bithorax complex (BX-C), which consists of three homeotic genes Ubx, abd-A and Abd-B, are separated by boundaries that function as insulators. Most of the boundaries contain binding sites for the architectural protein CTCF, which is conserved for higher eukaryotes. As was shown previously, the CTCF sites determine the insulator activity of the boundaries of the Abd-B regulatory region. In this study, it was shown that fragments of the Fab-3 and Fab-4 boundaries of the abd-A regulatory region, containing CTCF binding sites, are not effective insulators.
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Affiliation(s)
- O V Kyrchanova
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
| | - N Y Postika
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - V V Sokolov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - P G Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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19
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Joshi R, Sipani R, Bakshi A. Roles of Drosophila Hox Genes in the Assembly of Neuromuscular Networks and Behavior. Front Cell Dev Biol 2022; 9:786993. [PMID: 35071230 PMCID: PMC8777297 DOI: 10.3389/fcell.2021.786993] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes have been known for specifying the anterior-posterior axis (AP) in bilaterian body plans. Studies in vertebrates have shown their importance in developing region-specific neural circuitry and diversifying motor neuron pools. In Drosophila, they are instrumental for segment-specific neurogenesis and myogenesis early in development. Their robust expression in differentiated neurons implied their role in assembling region-specific neuromuscular networks. In the last decade, studies in Drosophila have unequivocally established that Hox genes go beyond their conventional functions of generating cellular diversity along the AP axis of the developing central nervous system. These roles range from establishing and maintaining the neuromuscular networks to controlling their function by regulating the motor neuron morphology and neurophysiology, thereby directly impacting the behavior. Here we summarize the limited knowledge on the role of Drosophila Hox genes in the assembly of region-specific neuromuscular networks and their effect on associated behavior.
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Affiliation(s)
- Rohit Joshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India
| | - Rashmi Sipani
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Asif Bakshi
- Laboratory of Drosophila Neural Development, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.,Graduate Studies, Manipal Academy of Higher Education, Manipal, India
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20
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Tögel M, Pass G, Paululat A. Wing hearts in four-winged Ultrabithorax-mutant flies-the role of Hox genes in wing heart specification. Genetics 2022; 220:iyab191. [PMID: 34791231 PMCID: PMC8733458 DOI: 10.1093/genetics/iyab191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/18/2021] [Indexed: 11/14/2022] Open
Abstract
Wings are probably the most advanced evolutionary novelty in insects. In the fruit fly Drosophila melanogaster, proper development of wings requires the activity of so-called wing hearts located in the scutellum of the thorax. Immediately after the imaginal ecdysis, these accessory circulatory organs remove hemolymph and apoptotic epidermal cells from the premature wings through their pumping action. This clearing process is essential for the formation of functional wing blades. Mutant flies that lack intact wing hearts are flightless and display malformed wings. The embryonic wing heart progenitors originate from two adjacent parasegments corresponding to the later second and third thoracic segments. However, adult dipterian flies harbor only one pair of wings and only one pair of associated wing hearts in the second thoracic segment. Here we show that the specification of WHPs depends on the regulatory activity of the Hox gene Ultrabithorax. Furthermore, we analyzed the development of wing hearts in the famous four-winged Ultrabithorax (Ubx) mutant, which was first discovered by Ed Lewis in the 1970s. In these flies, the third thoracic segment is homeotically transformed into a second thoracic segment resulting in a second pair of wings instead of the club-shaped halteres. We show that a second pair of functional wing hearts is formed in the transformed third thoracic segment and that all wing hearts originate from the wild-type population of wing heart progenitor cells.
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Affiliation(s)
- Markus Tögel
- Department of Biology, Zoology/Developmental Biology, University of Osnabrück, Osnabrück D-49069, Germany
| | - Günther Pass
- Department of Evolutionary Biology, University of Vienna, Althanstraße 14, Vienna A-1090, Austria
| | - Achim Paululat
- Department of Biology, Zoology/Developmental Biology, University of Osnabrück, Osnabrück D-49069, Germany
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21
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Verma S, Pathak RU, Mishra RK. Genomic organization of the autonomous regulatory domain of eyeless locus in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2021; 11:6375946. [PMID: 34570231 PMCID: PMC8664461 DOI: 10.1093/g3journal/jkab338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 09/09/2021] [Indexed: 11/29/2022]
Abstract
In Drosophila, expression of eyeless (ey) gene is restricted to the developing eyes and central nervous system. However, the flanking genes, myoglianin (myo), and bent (bt) have different temporal and spatial expression patterns as compared to the ey. How distinct regulation of ey is maintained is mostly unknown. Earlier, we have identified a boundary element intervening myo and ey genes (ME boundary) that prevents the crosstalk between the cis-regulatory elements of myo and ey genes. In the present study, we further searched for the cis-elements that define the domain of ey and maintain its expression pattern. We identify another boundary element between ey and bt, the EB boundary. The EB boundary separates the regulatory landscapes of ey and bt genes. The two boundaries, ME and EB, show a long-range interaction as well as interact with the nuclear architecture. This suggests functional autonomy of the ey locus and its insulation from differentially regulated flanking regions. We also identify a new Polycomb Response Element, the ey-PRE, within the ey domain. The expression state of the ey gene, once established during early development is likely to be maintained with the help of ey-PRE. Our study proposes a general regulatory mechanism by which a gene can be maintained in a functionally independent chromatin domain in gene-rich euchromatin.
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Affiliation(s)
- Shreekant Verma
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Rashmi U Pathak
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Rakesh K Mishra
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
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22
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Hajirnis N, Mishra RK. Homeotic Genes: Clustering, Modularity, and Diversity. Front Cell Dev Biol 2021; 9:718308. [PMID: 34458272 PMCID: PMC8386295 DOI: 10.3389/fcell.2021.718308] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Hox genes code for transcription factors and are evolutionarily conserved. They regulate a plethora of downstream targets to define the anterior-posterior (AP) body axis of a developing bilaterian embryo. Early work suggested a possible role of clustering and ordering of Hox to regulate their expression in a spatially restricted manner along the AP axis. However, the recent availability of many genome assemblies for different organisms uncovered several examples that defy this constraint. With recent advancements in genomics, the current review discusses the arrangement of Hox in various organisms. Further, we revisit their discovery and regulation in Drosophila melanogaster. We also review their regulation in different arthropods and vertebrates, with a significant focus on Hox expression in the crustacean Parahyale hawaiensis. It is noteworthy that subtle changes in the levels of Hox gene expression can contribute to the development of novel features in an organism. We, therefore, delve into the distinct regulation of these genes during primary axis formation, segment identity, and extra-embryonic roles such as in the formation of hair follicles or misregulation leading to cancer. Toward the end of each section, we emphasize the possibilities of several experiments involving various organisms, owing to the advancements in the field of genomics and CRISPR-based genome engineering. Overall, we present a holistic view of the functioning of Hox in the animal world.
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Affiliation(s)
- Nikhil Hajirnis
- CSIR – Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India
| | - Rakesh K. Mishra
- CSIR – Centre for Cellular and Molecular Biology (CCMB), Hyderabad, India
- AcSIR – Academy of Scientific and Innovative Research, Ghaziabad, India
- Tata Institute for Genetics and Society (TIGS), Bangalore, India
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23
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Kyrchanova O, Klimenko N, Postika N, Bonchuk A, Zolotarev N, Maksimenko O, Georgiev P. Drosophila architectural protein CTCF is not essential for fly survival and is able to function independently of CP190. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2021; 1864:194733. [PMID: 34311130 DOI: 10.1016/j.bbagrm.2021.194733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 12/20/2022]
Abstract
CTCF is the most likely ancestor of proteins that contain large clusters of C2H2 zinc finger domains (C2H2) and is conserved among most bilateral organisms. In mammals, CTCF functions as the main architectural protein involved in the organization of topology-associated domains (TADs). In vertebrates and Drosophila, CTCF is involved in the regulation of homeotic genes. Previously, it was found that null mutations in the dCTCF gene died as pharate adults, which failed to eclose from their pupal case, or shortly after hatching of adults. Here, we obtained several new null dCTCF mutations and found that the complete inactivation of dCTCF appears is limited mainly to phenotypic manifestations of the Abd-B gene and fertility of adult flies. Many modifiers that are not associated with an independent phenotypic manifestation can significantly enhance the expressivity of the null dCTCF mutations, indicating that other architectural proteins are able to functionally compensate for dCTCF inactivation in Drosophila. We also mapped the 715-735 aa region of dCTCF as being essential for the interaction with the BTB (Broad-Complex, Tramtrack, and Bric a brac) and microtubule-targeting (M) domains of the CP190 protein, which binds to many architectural proteins. However, the mutational analysis showed that the interaction with CP190 was not important for the functional activity of dCTCF in vivo.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Natalia Klimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Artem Bonchuk
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia; Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Nikolay Zolotarev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Oksana Maksimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.
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24
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Rajpurkar AR, Mateo LJ, Murphy SE, Boettiger AN. Deep learning connects DNA traces to transcription to reveal predictive features beyond enhancer-promoter contact. Nat Commun 2021; 12:3423. [PMID: 34103507 PMCID: PMC8187657 DOI: 10.1038/s41467-021-23831-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 05/19/2021] [Indexed: 11/27/2022] Open
Abstract
Chromatin architecture plays an important role in gene regulation. Recent advances in super-resolution microscopy have made it possible to measure chromatin 3D structure and transcription in thousands of single cells. However, leveraging these complex data sets with a computationally unbiased method has been challenging. Here, we present a deep learning-based approach to better understand to what degree chromatin structure relates to transcriptional state of individual cells. Furthermore, we explore methods to "unpack the black box" to determine in an unbiased manner which structural features of chromatin regulation are most important for gene expression state. We apply this approach to an Optical Reconstruction of Chromatin Architecture dataset of the Bithorax gene cluster in Drosophila and show it outperforms previous contact-focused methods in predicting expression state from 3D structure. We find the structural information is distributed across the domain, overlapping and extending beyond domains identified by prior genetic analyses. Individual enhancer-promoter interactions are a minor contributor to predictions of activity.
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Affiliation(s)
- Aparna R Rajpurkar
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Leslie J Mateo
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Sedona E Murphy
- Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
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25
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Fujioka M, Nezdyur A, Jaynes JB. An insulator blocks access to enhancers by an illegitimate promoter, preventing repression by transcriptional interference. PLoS Genet 2021; 17:e1009536. [PMID: 33901190 PMCID: PMC8102011 DOI: 10.1371/journal.pgen.1009536] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 05/06/2021] [Accepted: 04/06/2021] [Indexed: 01/09/2023] Open
Abstract
Several distinct activities and functions have been described for chromatin insulators, which separate genes along chromosomes into functional units. Here, we describe a novel mechanism of functional separation whereby an insulator prevents gene repression. When the homie insulator is deleted from the end of a Drosophila even skipped (eve) locus, a flanking P-element promoter is activated in a partial eve pattern, causing expression driven by enhancers in the 3’ region to be repressed. The mechanism involves transcriptional read-through from the flanking promoter. This conclusion is based on the following. Read-through driven by a heterologous enhancer is sufficient to repress, even when homie is in place. Furthermore, when the flanking promoter is turned around, repression is minimal. Transcriptional read-through that does not produce anti-sense RNA can still repress expression, ruling out RNAi as the mechanism in this case. Thus, transcriptional interference, caused by enhancer capture and read-through when the insulator is removed, represses eve promoter-driven expression. We also show that enhancer-promoter specificity and processivity of transcription can have decisive effects on the consequences of insulator removal. First, a core heat shock 70 promoter that is not activated well by eve enhancers did not cause read-through sufficient to repress the eve promoter. Second, these transcripts are less processive than those initiated at the P-promoter, measured by how far they extend through the eve locus, and so are less disruptive. These results highlight the importance of considering transcriptional read-through when assessing the effects of insulators on gene expression. Several distinct activities and functions have been described for chromatin insulators, which are regulatory DNA elements that separate genes along chromosomes into functional units. Here, we describe how insulators can prevent repression of one gene by preventing inappropriate transcription of another gene, without blocking read-through of transcription per se. When the insulator homie is deleted from the end of a transgenic eve locus, a flanking transposable element promoter is activated by eve enhancers, causing repression of the eve promoter. The mechanism involves transcriptional read-through from the flanking promoter, which disrupts normal eve enhancer-promoter activities. When the flanking promoter is turned around, repression of eve is minimal. Thus, transcriptional interference, caused by enhancer capture and read-through when the insulator is removed, represses the eve promoter. These results show a novel role for transcriptional read-through in the effects of insulators on gene expression.
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Affiliation(s)
- Miki Fujioka
- Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Anastasiya Nezdyur
- Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - James B. Jaynes
- Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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26
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Matharu NK, Yadav S, Kumar M, Mishra RK. Role of vertebrate GAGA associated factor (vGAF) in early development of zebrafish. Cells Dev 2021; 166:203682. [PMID: 33994355 DOI: 10.1016/j.cdev.2021.203682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/29/2021] [Accepted: 04/21/2021] [Indexed: 11/29/2022]
Abstract
Homeotic genes and their genomic organization show remarkable conservation across bilaterians. Consequently, the regulatory mechanisms, which control hox gene expression, are also highly conserved. The crucial presence of conserved GA rich motifs between Hox genes has been previously observed but what factor binds to these is still unknown. Previously we have reported that the vertebrate homologue of Drosophila Trl-GAF preferentially binds to GA rich regions in Evx2-hoxd13 intergenic region of vertebrate HoxD cluster. In this study, we show that the vertebrate-GAF (v-GAF) binds at known cis-regulatory elements in the HoxD complex of zebrafish and mouse. We further used morpholino based knockdown and CRISPR-cas9 knockout technique to deplete the v-GAF in zebrafish. We checked expression of the HoxD genes and found gain of the HoxD4 gene in GAF knockout embryos. Further, we partially rescued the morphological phenotypes in GAF depleted embryos by providing GAF mRNA. Our results show that GAF binds at intergenic regions of the HoxD complex and is important for maintaining the spatial domains of HoxD4 expression during embryonic development.
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Affiliation(s)
- Navneet K Matharu
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India
| | - Sonu Yadav
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcCSIR), India
| | - Megha Kumar
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcCSIR), India
| | - Rakesh K Mishra
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcCSIR), India.
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27
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Piunti A, Shilatifard A. The roles of Polycomb repressive complexes in mammalian development and cancer. Nat Rev Mol Cell Biol 2021; 22:326-345. [PMID: 33723438 DOI: 10.1038/s41580-021-00341-1] [Citation(s) in RCA: 195] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2021] [Indexed: 12/14/2022]
Abstract
More than 80 years ago, the first Polycomb-related phenotype was identified in Drosophila melanogaster. Later, a group of diverse genes collectively called Polycomb group (PcG) genes were identified based on common mutant phenotypes. PcG proteins, which are well-conserved in animals, were originally characterized as negative regulators of gene transcription during development and subsequently shown to function in various biological processes; their deregulation is associated with diverse phenotypes in development and in disease, especially cancer. PcG proteins function on chromatin and can form two distinct complexes with different enzymatic activities: Polycomb repressive complex 1 (PRC1) is a histone ubiquitin ligase and PRC2 is a histone methyltransferase. Recent studies have revealed the existence of various mutually exclusive PRC1 and PRC2 variants. In this Review, we discuss new concepts concerning the biochemical and molecular functions of these new PcG complex variants, and how their epigenetic activities are involved in mammalian development and cancer.
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Affiliation(s)
- Andrea Piunti
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ali Shilatifard
- Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. .,Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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Khan S, Sowpati DT, Srinivasan A, Soujanya M, Mishra RK. Long-Read Genome Sequencing and Assembly of Leptopilina boulardi: A Specialist Drosophila Parasitoid. G3 (BETHESDA, MD.) 2020; 10:1485-1494. [PMID: 32217632 PMCID: PMC7202025 DOI: 10.1534/g3.120.401151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 03/15/2020] [Indexed: 02/06/2023]
Abstract
Leptopilinaboulardi (Hymenoptera: Figitidae) is a specialist parasitoid of Drosophila The Drosophila-Leptopilina system has emerged as a suitable model for understanding several aspects of host-parasitoid biology. However, a good quality genome of the wasp counterpart was lacking. Here, we report a whole-genome assembly of L. boulardi to bring it in the scope of the applied and fundamental research on Drosophila parasitoids with access to epigenomics and genome editing tools. The 375Mb draft genome has an N50 of 275Kb with 6315 scaffolds >500bp and encompasses >95% complete BUSCOs. Using a combination of ab-initio and RNA-Seq based methods, 25259 protein-coding genes were predicted and 90% (22729) of them could be annotated with at least one function. We demonstrate the quality of the assembled genome by recapitulating the phylogenetic relationship of L. boulardi with other Hymenopterans. The key developmental regulators like Hox genes and sex determination genes are well conserved in L. boulardi, and so is the basic toolkit for epigenetic regulation. The search for epigenetic regulators has also revealed that L. boulardi genome possesses DNMT1 (maintenance DNA methyltransferase), DNMT2 (tRNA methyltransferase) but lacks the de novo DNA methyltransferase (DNMT3). Also, the heterochromatin protein 1 family appears to have expanded as compared to other hymenopterans. The draft genome of L. boulardi (Lb17) will expedite the research on Drosophila parasitoids. This genome resource and early indication of epigenetic aspects in its specialization make it an interesting system to address a variety of questions on host-parasitoid biology.
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Affiliation(s)
- Shagufta Khan
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad - 500007, Telangana, India
| | - Divya Tej Sowpati
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad - 500007, Telangana, India
| | - Arumugam Srinivasan
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad - 500007, Telangana, India
| | - Mamilla Soujanya
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad - 500007, Telangana, India
| | - Rakesh K Mishra
- CSIR - Centre for Cellular and Molecular Biology, Hyderabad - 500007, Telangana, India
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Tian L, Rahman SR, Ezray BD, Franzini L, Strange JP, Lhomme P, Hines HM. A homeotic shift late in development drives mimetic color variation in a bumble bee. Proc Natl Acad Sci U S A 2019; 116:11857-11865. [PMID: 31043564 PMCID: PMC6575597 DOI: 10.1073/pnas.1900365116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Natural phenotypic radiations, with their high diversity and convergence, are well-suited for informing how genomic changes translate to natural phenotypic variation. New genomic tools enable discovery in such traditionally nonmodel systems. Here, we characterize the genomic basis of color pattern variation in bumble bees (Hymenoptera, Apidae, Bombus), a group that has undergone extensive convergence of setal color patterns as a result of Müllerian mimicry. In western North America, multiple species converge on local mimicry patterns through parallel shifts of midabdominal segments from red to black. Using genome-wide association, we establish that a cis-regulatory locus between the abdominal fate-determining Hox genes, abd-A and Abd-B, controls the red-black color switch in a western species, Bombus melanopygus Gene expression analysis reveals distinct shifts in Abd-B aligned with the duration of setal pigmentation at the pupal-adult transition. This results in atypical anterior Abd-B expression, a late developmental homeotic shift. Changing expression of Hox genes can have widespread effects, given their important role across segmental phenotypes; however, the late timing reduces this pleiotropy, making Hox genes suitable targets. Analysis of this locus across mimics and relatives reveals that other species follow independent genetic routes to obtain the same phenotypes.
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Affiliation(s)
- Li Tian
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
| | | | - Briana D Ezray
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
| | - Luca Franzini
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
| | - James P Strange
- United States Department of Agriculture-Agricultural Research Service Pollinating Insects Research Unit, Utah State University, Logan, UT 84322
| | - Patrick Lhomme
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
- Biodiversity and Crop Improvement Program, International Center of Agricultural Research in the Dry Areas, 10112 Rabat, Morocco
| | - Heather M Hines
- Department of Biology, The Pennsylvania State University, University Park, PA 16802;
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802
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Wang H, Hu H, Xiang Z, Lu C, Dai F, Tong X. Identification and characterization of a new long noncoding RNA iab-1 in the Hox cluster of silkworm, Bombyx mori identification of iab-1. J Cell Biochem 2019; 120:17283-17292. [PMID: 31106470 DOI: 10.1002/jcb.28990] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/06/2019] [Accepted: 04/11/2019] [Indexed: 02/04/2023]
Abstract
Long noncoding RNAs (lncRNAs) areinvolvedin a variety of biological processes. In silkworm, numerous lncRNAs have been predicted through deep transcriptome sequencing, but no functional role has been experimentally validated yet. Here, we characterized a new lncRNA iab-1 that was mainly encoded by the intergenic region between Bmabd-A and Bmabd-B in the Homeobox (Hox) cluster of the silkworm, Bombyx mori. More than seven alternative splicing isoforms of lncRNA iab-1 were cloned, which were subgrouped into types 1 and 2 based on the location of the 3'-ends. The iab-1 was expressed at a low level, but the expression of iab-1 peaked at several specific development stages, including 3 to 4 days during the embryonic stage, stages before fourth molting, and the sixth hour after the fourth molting, and early stages during metamorphosis. It was highly expressed in the nervus and epidermis, especially the epidermis of the posterior abdomen at the fourth instar premolting stage. The relationship between iab-1 and nearby Hox genes was analyzed at different developmental stages. Iab-1 expression was highly associated with Bmabd-A as well as Bmabd-B in the embryonic and larval stages, while this association was decreased at the metamorphic stage; iab-1 expression was highly associated with BmUbx only in the embryonic stage. Downregulation of iab-1 expression by small interfering RNA led to the death of most of the treated individuals at the larval stage, suggesting that iab-1 transcript expression might be involved in certain relevant physiological processes. The expression of Bmabd-A and Bmabd-B did not change in iab-1 downregulated individuals, indicating that the relevance between the two genes and iab-1 was not induced by iab-1 transcript. Collectively, the results showed that the newly identified iab-1 may be involved in some physiological processes, and the interaction between iab-1 and Hox genes was also preliminarily analyzed.
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Affiliation(s)
- Honglei Wang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Hai Hu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Fangyin Dai
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
| | - Xiaoling Tong
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing, China
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Mateo LJ, Murphy SE, Hafner A, Cinquini IS, Walker CA, Boettiger AN. Visualizing DNA folding and RNA in embryos at single-cell resolution. Nature 2019; 568:49-54. [PMID: 30886393 PMCID: PMC6556380 DOI: 10.1038/s41586-019-1035-4] [Citation(s) in RCA: 271] [Impact Index Per Article: 54.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 02/25/2019] [Indexed: 01/09/2023]
Abstract
The establishment of cell types during development requires precise interactions between genes and distal regulatory sequences. We have a limited understanding of how these interactions look in three dimensions, vary across cell types in complex tissue, and relate to transcription. Here we describe optical reconstruction of chromatin architecture (ORCA), a method that can trace the DNA path in single cells with nanoscale accuracy and genomic resolution reaching two kilobases. We used ORCA to study a Hox gene cluster in cryosectioned Drosophila embryos and labelled around 30 RNA species in parallel. We identified cell-type-specific physical borders between active and Polycomb-repressed DNA, and unexpected Polycomb-independent borders. Deletion of Polycomb-independent borders led to ectopic enhancer-promoter contacts, aberrant gene expression, and developmental defects. Together, these results illustrate an approach for high-resolution, single-cell DNA domain analysis in vivo, identify domain structures that change with cell identity, and show that border elements contribute to the formation of physical domains in Drosophila.
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Affiliation(s)
- Leslie J Mateo
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Sedona E Murphy
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Antonina Hafner
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
| | - Isaac S Cinquini
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Carly A Walker
- Department of Developmental Biology, Stanford University, Stanford, CA, USA
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Dorafshan E, Kahn TG, Glotov A, Savitsky M, Walther M, Reuter G, Schwartz YB. Ash1 counteracts Polycomb repression independent of histone H3 lysine 36 methylation. EMBO Rep 2019; 20:embr.201846762. [PMID: 30833342 DOI: 10.15252/embr.201846762] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 01/31/2019] [Accepted: 02/05/2019] [Indexed: 12/11/2022] Open
Abstract
Polycomb repression is critical for metazoan development. Equally important but less studied is the Trithorax system, which safeguards Polycomb target genes from the repression in cells where they have to remain active. It was proposed that the Trithorax system acts via methylation of histone H3 at lysine 4 and lysine 36 (H3K36), thereby inhibiting histone methyltransferase activity of the Polycomb complexes. Here we test this hypothesis by asking whether the Trithorax group protein Ash1 requires H3K36 methylation to counteract Polycomb repression. We show that Ash1 is the only Drosophila H3K36-specific methyltransferase necessary to prevent excessive Polycomb repression of homeotic genes. Unexpectedly, our experiments reveal no correlation between the extent of H3K36 methylation and the resistance to Polycomb repression. Furthermore, we find that complete substitution of the zygotic histone H3 with a variant in which lysine 36 is replaced by arginine does not cause excessive repression of homeotic genes. Our results suggest that the model, where the Trithorax group proteins methylate histone H3 to inhibit the histone methyltransferase activity of the Polycomb complexes, needs revision.
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Affiliation(s)
| | - Tatyana G Kahn
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | | | - Matthias Walther
- Institute of Developmental Genetics, Martin-Luther University of Halle-Wittenberg, Halle, Germany.,Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Gunter Reuter
- Institute of Developmental Genetics, Martin-Luther University of Halle-Wittenberg, Halle, Germany
| | - Yuri B Schwartz
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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Fedotova A, Clendinen C, Bonchuk A, Mogila V, Aoki T, Georgiev P, Schedl P. Functional dissection of the developmentally restricted BEN domain chromatin boundary factor Insensitive. Epigenetics Chromatin 2019; 12:2. [PMID: 30602385 PMCID: PMC6317261 DOI: 10.1186/s13072-018-0249-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 12/19/2018] [Indexed: 02/06/2023] Open
Abstract
Background Boundaries in the Drosophila bithorax complex delimit autonomous regulatory domains that activate the parasegment (PS)-specific expression of homeotic genes. The Fab-7 boundary separates the iab-6 and iab-7 regulatory domains that control Abd-B expression in PS11 and PS12. This boundary is composed of multiple functionally redundant elements and has two key activities: it blocks crosstalk between iab-6 and iab-7 and facilitates boundary bypass. Results Here, we have used a structure–function approach to elucidate the biochemical properties and the in vivo activities of a conserved BEN domain protein, Insensitive, that is associated with Fab-7. Our biochemical studies indicate that in addition to the C-terminal BEN DNA-binding domain, Insv has two domains that mediate multimerization: one is a coiled-coil domain in the N-terminus, and the other is next to the BEN domain. These multimerization domains enable Insv to bind simultaneously to two canonical 8-bp recognition motifs, as well as to a ~ 100-bp non-canonical recognition sequence. They also mediate the assembly of higher-order multimers in the presence of DNA. Transgenic proteins lacking the N-terminal coiled-coil domain are compromised for boundary function in vivo. We also show that Insv interacts directly with CP190, a protein previously implicated in the boundary functions of several DNA-binding proteins, including Su(Hw) and dCTCF. While CP190 interaction is required for Insv binding to a subset of sites on polytene chromosomes, it has only a minor role in the boundary activity of Insv in the context of Fab-7. Conclusions The subdivision of eukaryotic chromosomes into discrete topological domains depends upon the pairing of boundary elements. In flies, pairing interactions are specific and typically orientation dependent. They occur in cis between neighboring heterologous boundaries, and in trans between homologous boundaries. One potential mechanism for ensuring pairing-interaction specificity is the use of sequence-specific DNA-binding proteins that can bind simultaneously with two or more recognition sequences. Our studies indicate that Insv can assemble into a multivalent DNA-binding complex and that the N-terminal Insv multimerization domain is critical for boundary function. Electronic supplementary material The online version of this article (10.1186/s13072-018-0249-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna Fedotova
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Chaevia Clendinen
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Artem Bonchuk
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Vladic Mogila
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Tsutomu Aoki
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Pavel Georgiev
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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Postika N, Metzler M, Affolter M, Müller M, Schedl P, Georgiev P, Kyrchanova O. Boundaries mediate long-distance interactions between enhancers and promoters in the Drosophila Bithorax complex. PLoS Genet 2018; 14:e1007702. [PMID: 30540750 PMCID: PMC6306242 DOI: 10.1371/journal.pgen.1007702] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/26/2018] [Accepted: 11/16/2018] [Indexed: 11/18/2022] Open
Abstract
Drosophila bithorax complex (BX-C) is one of the best model systems for studying the role of boundaries (insulators) in gene regulation. Expression of three homeotic genes, Ubx, abd-A, and Abd-B, is orchestrated by nine parasegment-specific regulatory domains. These domains are flanked by boundary elements, which function to block crosstalk between adjacent domains, ensuring that they can act autonomously. Paradoxically, seven of the BX-C regulatory domains are separated from their gene target by at least one boundary, and must “jump over” the intervening boundaries. To understand the jumping mechanism, the Mcp boundary was replaced with Fab-7 and Fab-8. Mcp is located between the iab-4 and iab-5 domains, and defines the border between the set of regulatory domains controlling abd-A and Abd-B. When Mcp is replaced by Fab-7 or Fab-8, they direct the iab-4 domain (which regulates abd-A) to inappropriately activate Abd-B in abdominal segment A4. For the Fab-8 replacement, ectopic induction was only observed when it was inserted in the same orientation as the endogenous Fab-8 boundary. A similar orientation dependence for bypass activity was observed when Fab-7 was replaced by Fab-8. Thus, boundaries perform two opposite functions in the context of BX-C–they block crosstalk between neighboring regulatory domains, but at the same time actively facilitate long distance communication between the regulatory domains and their respective target genes. Drosophila bithorax complex (BX-C) is one of a few examples demonstrating in vivo role of boundary/insulator elements in organization of independent chromatin domains. BX-C contains three HOX genes, whose parasegment-specific pattern is controlled by cis-regulatory domains flanked by boundary/insulator elements. Since the boundaries ensure autonomy of adjacent domains, the presence of these elements poses a paradox: how do the domains bypass the intervening boundaries and contact their proper regulatory targets? According to the textbook model, BX-C regulatory domains are able to bypass boundaries because they harbor special promoter targeting sequences. However, contrary to this model, we show here that the boundaries themselves play an active role in directing regulatory domains to their appropriate HOX gene promoter.
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Affiliation(s)
- Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | | | | | | | - Paul Schedl
- Department of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- * E-mail: (PG); (OK)
| | - Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
- * E-mail: (PG); (OK)
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35
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From Flies to Mice: The Emerging Role of Non-Canonical PRC1 Members in Mammalian Development. EPIGENOMES 2018. [DOI: 10.3390/epigenomes2010004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Abstract
The question of how noncoding RNAs are involved in Polycomb group (PcG) and Trithorax group (TrxG) regulation has been on an extraordinary journey over the last three decades. Favored models have risen and fallen, and healthy debates have swept back and forth. The field has recently reached a critical mass of compelling data that throws light on several previously unresolved issues. The time is ripe for a fruitful combination of these findings with two other long-running avenues of research, namely the biochemical properties of the PcG/TrxG system and the application of theoretical mathematical models toward an understanding of the system's regulatory properties. I propose that integrating our current knowledge of noncoding RNA into a quantitative biochemical and theoretical framework for PcG and TrxG regulation has the potential to reconcile several apparently conflicting models and identifies fascinating questions for future research.
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Affiliation(s)
- Leonie Ringrose
- Integrated Research Institute for Life Sciences, Humboldt-Universität zu Berlin, 10115 Berlin, Germany;
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37
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Sex combs reduced (Scr) regulatory region of Drosophila revisited. Mol Genet Genomics 2017; 292:773-787. [DOI: 10.1007/s00438-017-1309-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 03/08/2017] [Indexed: 10/19/2022]
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Three-Dimensional Genome Organization and Function in Drosophila. Genetics 2017; 205:5-24. [PMID: 28049701 PMCID: PMC5223523 DOI: 10.1534/genetics.115.185132] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/15/2016] [Indexed: 12/18/2022] Open
Abstract
Understanding how the metazoan genome is used during development and cell differentiation is one of the major challenges in the postgenomic era. Early studies in Drosophila suggested that three-dimensional (3D) chromosome organization plays important regulatory roles in this process and recent technological advances started to reveal connections at the molecular level. Here we will consider general features of the architectural organization of the Drosophila genome, providing historical perspective and insights from recent work. We will compare the linear and spatial segmentation of the fly genome and focus on the two key regulators of genome architecture: insulator components and Polycomb group proteins. With its unique set of genetic tools and a compact, well annotated genome, Drosophila is poised to remain a model system of choice for rapid progress in understanding principles of genome organization and to serve as a proving ground for development of 3D genome-engineering techniques.
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Pervasive Behavioral Effects of MicroRNA Regulation in Drosophila. Genetics 2017; 206:1535-1548. [PMID: 28468905 PMCID: PMC5500149 DOI: 10.1534/genetics.116.195776] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 04/23/2017] [Indexed: 11/18/2022] Open
Abstract
Picao-Osorio et al. reveal pervasive effects of microRNA regulation on complex locomotor behaviors in Drosophila larvae: over 40% of microRNAs display... The effects of microRNA (miRNA) regulation on the genetic programs underlying behavior remain largely unexplored. Despite this, recent work in Drosophila shows that mutation of a single miRNA locus (miR-iab4/iab8) affects the capacity of the larva to correct its orientation if turned upside down (self-righting, SR), suggesting that other miRNAs might also be involved in behavioral control. Here we explore this possibility, studying early larval SR behavior in a collection of 81 Drosophila miRNA mutants covering almost the entire miRNA complement of the late embryo. Unexpectedly, we observe that >40% of all miRNAs tested significantly affect SR time, revealing pervasive behavioral effects of miRNA regulation in the early larva. Detailed analyses of those miRNAs affecting SR behavior (SR-miRNAs) show that individual miRNAs can affect movement in different ways, suggesting that specific molecular and cellular elements are affected by individual miRNA mutations. Furthermore, gene expression analysis shows that the Hox gene Abdominal-B (Abd-B) represents one of the targets deregulated by several SR-miRNAs. Our work thus reveals pervasive effects of miRNA regulation on a complex innate behavior in Drosophila and suggests that miRNAs may be core components of the genetic programs underlying behavioral control in other animals too.
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40
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Wang H, Tong X, Liu M, Hu H, Li Z, Xiang Z, Dai F, Lu C. Fine Mapping of a Degenerated Abdominal Legs Mutant (Edl) in Silkworm, Bombyx mori. PLoS One 2017; 12:e0169224. [PMID: 28081147 PMCID: PMC5231277 DOI: 10.1371/journal.pone.0169224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/13/2016] [Indexed: 12/05/2022] Open
Abstract
In insects, abdominal appendages, also called prolegs, vary due to adaptive evolution. Mutations on prolegs within species provide insights to better understand the mechanisms underlying appendage development and diversity. In silkworm Bombyx mori, extra-crescents and degenerated abdominal legs (Edl) mutant, belonging to the E pseudoallele group, is a spontaneous mutation that adds crescents and degenerates prolegs on the third abdominal segment (A3). This mutation may be a homeotic transformation of A3 to A2. In this study, the Edl locus was mapped within approximately a 211 Kb region that is 10 Kb upstream of Bmabdominal-A (Bmabd-A). RT-quantitative PCR (RT-qPCR) and Western blot analysis of Bmabd-A expression showed a slight but significant decrease, while the expression of BmUltrabithorax (BmUbx) was up-regulated in the Edl mutant compared to wildtype (Dazao). Moreover, we also found that BmDistal-less (BmDll), which regulated the development of distal proleg structures, was missing at the tips of the A3 prolegs in the Edl mutant compared to BmDll expression in normally developed prolegs in both the wildtype and mutant. Collectively, we identified approximately a 211 Kb region in the Edl locus that regulates BmUbx and Bmabd-A expression and found that changes in BmUbx and Bmabd-A expression may lead to the loss of distal proleg structures in B. mori.
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Affiliation(s)
- Honglei Wang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Xiaoling Tong
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Meijing Liu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Hai Hu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Zhiquan Li
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Fangyin Dai
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
- * E-mail: (FD); (CL)
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
- * E-mail: (FD); (CL)
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Different Evolutionary Strategies To Conserve Chromatin Boundary Function in the Bithorax Complex. Genetics 2016; 205:589-603. [PMID: 28007886 PMCID: PMC5289839 DOI: 10.1534/genetics.116.195586] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/12/2016] [Indexed: 12/01/2022] Open
Abstract
Chromatin boundary elements subdivide chromosomes in multicellular organisms into physically independent domains. In addition to this architectural function, these elements also play a critical role in gene regulation. Here we investigated the evolution of a Drosophila Bithorax complex boundary element called Fab-7, which is required for the proper parasegment specific expression of the homeotic Abd-B gene. Using a “gene” replacement strategy, we show that Fab-7 boundaries from two closely related species, D. erecta and D. yakuba, and a more distant species, D. pseudoobscura, are able to substitute for the melanogaster boundary. Consistent with this functional conservation, the two known Fab-7 boundary factors, Elba and LBC, have recognition sequences in the boundaries from all species. However, the strategies used for maintaining binding and function in the face of sequence divergence is different. The first is conventional, and depends upon conservation of the 8 bp Elba recognition sequence. The second is unconventional, and takes advantage of the unusually large and flexible sequence recognition properties of the LBC boundary factor, and the deployment of multiple LBC recognition elements in each boundary. In the former case, binding is lost when the recognition sequence is altered. In the latter case, sequence divergence is accompanied by changes in the number, relative affinity, and location of the LBC recognition elements.
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Poynter ST, Kadoch C. Polycomb and trithorax opposition in development and disease. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:659-688. [PMID: 27581385 DOI: 10.1002/wdev.244] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 05/07/2016] [Accepted: 06/02/2016] [Indexed: 01/08/2023]
Abstract
Early discoveries in chromatin biology and epigenetics heralded new insights into organismal development. From these studies, two mediators of cellular differentiation were discovered: the Polycomb group (PcG) of transcriptional repressors, and the trithorax group (trxG) of transcriptional activators. These protein families, while opposed in function, work together to coordinate the appropriate cellular developmental programs that allow for both embryonic stem cell self-renewal and differentiation. Recently, both the PcG and trxG chromatin modulators have been observed to be deregulated in a wide spectrum diseases including developmental disorders and cancer. To understand the impact of these findings we outline the past, present, and future. WIREs Dev Biol 2016, 5:659-688. doi: 10.1002/wdev.244 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Steven T Poynter
- Chemical Biology Program, Harvard Medical School, Boston, MA, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Cigall Kadoch
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. .,Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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43
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Kahn TG, Dorafshan E, Schultheis D, Zare A, Stenberg P, Reim I, Pirrotta V, Schwartz YB. Interdependence of PRC1 and PRC2 for recruitment to Polycomb Response Elements. Nucleic Acids Res 2016; 44:10132-10149. [PMID: 27557709 PMCID: PMC5137424 DOI: 10.1093/nar/gkw701] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 07/26/2016] [Accepted: 07/28/2016] [Indexed: 12/31/2022] Open
Abstract
Polycomb Group (PcG) proteins are epigenetic repressors essential for control of development and cell differentiation. They form multiple complexes of which PRC1 and PRC2 are evolutionary conserved and obligatory for repression. The targeting of PRC1 and PRC2 is poorly understood and was proposed to be hierarchical and involve tri-methylation of histone H3 (H3K27me3) and/or monoubiquitylation of histone H2A (H2AK118ub). Here, we present a strict test of this hypothesis using the Drosophila model. We discover that neither H3K27me3 nor H2AK118ub is required for targeting PRC complexes to Polycomb Response Elements (PREs). We find that PRC1 can bind PREs in the absence of PRC2 but at many PREs PRC2 requires PRC1 to be targeted. We show that one role of H3K27me3 is to allow PcG complexes anchored at PREs to interact with surrounding chromatin. In contrast, the bulk of H2AK118ub is unrelated to PcG repression. These findings radically change our view of how PcG repression is targeted and suggest that PRC1 and PRC2 can communicate independently of histone modifications.
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Affiliation(s)
- Tatyana G Kahn
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Eshagh Dorafshan
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Dorothea Schultheis
- Friedrich-Alexander University of Erlangen-Nürnberg, Department of Biology, Division of Developmental Biology, Erlangen, D-91058, Germany
| | - Aman Zare
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
| | - Per Stenberg
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden.,Division of CBRN Defense and Security, Swedish Defense Research Agency, FOI, Umeå, 906 21, Sweden
| | - Ingolf Reim
- Friedrich-Alexander University of Erlangen-Nürnberg, Department of Biology, Division of Developmental Biology, Erlangen, D-91058, Germany
| | - Vincenzo Pirrotta
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Yuri B Schwartz
- Department of Molecular Biology, Umeå University, Umeå, 901 87, Sweden
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44
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Guerreiro I, Gitto S, Novoa A, Codourey J, Nguyen Huynh TH, Gonzalez F, Milinkovitch MC, Mallo M, Duboule D. Reorganisation of Hoxd regulatory landscapes during the evolution of a snake-like body plan. eLife 2016; 5. [PMID: 27476854 PMCID: PMC4969037 DOI: 10.7554/elife.16087] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 07/10/2016] [Indexed: 12/15/2022] Open
Abstract
Within land vertebrate species, snakes display extreme variations in their body plan, characterized by the absence of limbs and an elongated morphology. Such a particular interpretation of the basic vertebrate body architecture has often been associated with changes in the function or regulation of Hox genes. Here, we use an interspecies comparative approach to investigate different regulatory aspects at the snake HoxD locus. We report that, unlike in other vertebrates, snake mesoderm-specific enhancers are mostly located within the HoxD cluster itself rather than outside. In addition, despite both the absence of limbs and an altered Hoxd gene regulation in external genitalia, the limb-associated bimodal HoxD chromatin structure is maintained at the snake locus. Finally, we show that snake and mouse orthologous enhancer sequences can display distinct expression specificities. These results show that vertebrate morphological evolution likely involved extensive reorganisation at Hox loci, yet within a generally conserved regulatory framework.
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Affiliation(s)
- Isabel Guerreiro
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Sandra Gitto
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Ana Novoa
- Instituto Gulbenkian de Ciência, Lisbon, Portugal
| | - Julien Codourey
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | | | - Federico Gonzalez
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | | | - Moises Mallo
- Instituto Gulbenkian de Ciência, Lisbon, Portugal
| | - Denis Duboule
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland.,School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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45
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Distinct Roles of Chromatin Insulator Proteins in Control of the Drosophila Bithorax Complex. Genetics 2015; 202:601-17. [PMID: 26715665 DOI: 10.1534/genetics.115.179309] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 12/22/2015] [Indexed: 11/18/2022] Open
Abstract
Chromatin insulators are remarkable regulatory elements that can bring distant genomic sites together and block unscheduled enhancer-promoter communications. Insulators act via associated insulator proteins of two classes: sequence-specific DNA binding factors and "bridging" proteins. The latter are required to mediate interactions between distant insulator elements. Chromatin insulators are critical for correct expression of complex loci; however, their mode of action is poorly understood. Here, we use the Drosophila bithorax complex as a model to investigate the roles of the bridging proteins Cp190 and Mod(mdg4). The bithorax complex consists of three evolutionarily conserved homeotic genes Ubx, abd-A, and Abd-B, which specify anterior-posterior identity of the last thoracic and all abdominal segments of the fly. Looking at effects of CTCF, mod(mdg4), and Cp190 mutations on expression of the bithorax complex genes, we provide the first functional evidence that Mod(mdg4) acts in concert with the DNA binding insulator protein CTCF. We find that Mod(mdg4) and Cp190 are not redundant and may have distinct functional properties. We, for the first time, demonstrate that Cp190 is critical for correct regulation of the bithorax complex and show that Cp190 is required at an exceptionally strong Fub insulator to partition the bithorax complex into two topological domains.
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46
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Picao-Osorio J, Johnston J, Landgraf M, Berni J, Alonso CR. MicroRNA-encoded behavior in Drosophila. Science 2015; 350:815-20. [PMID: 26494171 PMCID: PMC4902127 DOI: 10.1126/science.aad0217] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/25/2015] [Indexed: 12/20/2022]
Abstract
The relationship between microRNA (miRNA) regulation and the specification of behavior is only beginning to be explored. We found that mutation of a single miRNA locus (miR-iab4/iab8) in Drosophila larvae affects the animal's capacity to correct its orientation if turned upside down (self-righting). One of the miRNA targets involved in this behavior is the Hox gene Ultrabithorax, whose derepression in two metameric neurons leads to self-righting defects. In vivo neural activity analysis reveals that these neurons, the self-righting node (SRN), have different activity patterns in wild type and miRNA mutants, whereas thermogenetic manipulation of SRN activity results in changes in self-righting behavior. Our work thus reveals a miRNA-encoded behavior and suggests that other miRNAs might also be involved in behavioral control in Drosophila and other species.
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Affiliation(s)
- Joao Picao-Osorio
- Sussex Neuroscience, School of Life Science, University of Sussex, Brighton BN1 9QG, UK
| | - Jamie Johnston
- Sussex Neuroscience, School of Life Science, University of Sussex, Brighton BN1 9QG, UK
| | - Matthias Landgraf
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Jimena Berni
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Claudio R Alonso
- Sussex Neuroscience, School of Life Science, University of Sussex, Brighton BN1 9QG, UK.
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47
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Singh NP, Mishra RK. Specific combinations of boundary element and Polycomb response element are required for the regulation of the Hox genes in Drosophila melanogaster. Mech Dev 2015; 138 Pt 2:141-150. [DOI: 10.1016/j.mod.2015.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 10/23/2022]
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48
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Kyrchanova O, Mogila V, Wolle D, Magbanua JP, White R, Georgiev P, Schedl P. The boundary paradox in the Bithorax complex. Mech Dev 2015; 138 Pt 2:122-132. [PMID: 26215349 PMCID: PMC4890074 DOI: 10.1016/j.mod.2015.07.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 02/08/2023]
Abstract
The parasegment-specific expression of the three Drosophila Bithorax complex homeotic genes is orchestrated by nine functionally autonomous regulatory domains. Functional autonomy depends upon special elements called boundaries or insulators that are located between each domain. The boundaries ensure the independent activity of each domain by blocking adventitious interactions with initiators, enhancers and silencers in the neighboring domains. However, this blocking activity poses a regulatory paradox--the Bithorax boundaries are also able to insulate promoters from regulatory interactions with enhancers and silencers and six of the nine Bithorax regulatory domains are separated from their target genes by at least one boundary element. Here we consider several mechanisms that have been suggested for how the Bithorax regulatory domains are able to bypass intervening boundary elements and direct the appropriate parasegment-specific temporal and spatial expression of their target gene.
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Affiliation(s)
- Olga Kyrchanova
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Vladic Mogila
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia; Nikolaev V.A. Sukhomlinsky National University, Department of Biology, Ukraine
| | - Daniel Wolle
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Jose Paolo Magbanua
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Robert White
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia; Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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49
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The elimination of an adult segment by the Hox gene Abdominal-B. Mech Dev 2015; 138 Pt 2:210-217. [DOI: 10.1016/j.mod.2015.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 07/31/2015] [Accepted: 08/01/2015] [Indexed: 11/19/2022]
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50
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The quest for mammalian Polycomb response elements: are we there yet? Chromosoma 2015; 125:471-96. [PMID: 26453572 PMCID: PMC4901126 DOI: 10.1007/s00412-015-0539-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 12/12/2022]
Abstract
A long-standing mystery in the field of Polycomb and Trithorax regulation is how these proteins, which are highly conserved between flies and mammals, can regulate several hundred equally highly conserved target genes, but recognise these targets via cis-regulatory elements that appear to show no conservation in their DNA sequence. These elements, termed Polycomb/Trithorax response elements (PRE/TREs or PREs), are relatively well characterised in flies, but their mammalian counterparts have proved to be extremely difficult to identify. Recent progress in this endeavour has generated a wealth of data and raised several intriguing questions. Here, we ask why and to what extent mammalian PREs are so different to those of the fly. We review recent advances, evaluate current models and identify open questions in the quest for mammalian PREs.
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