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Brown HE, Weasner BP, Weasner BM, Kumar JP. Polycomb safeguards imaginal disc specification through control of the Vestigial-Scalloped complex. Development 2023; 150:dev201872. [PMID: 37702007 PMCID: PMC10560572 DOI: 10.1242/dev.201872] [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: 04/18/2023] [Accepted: 09/04/2023] [Indexed: 09/14/2023]
Abstract
A fundamental goal of developmental biology is to understand how cell and tissue fates are specified. The imaginal discs of Drosophila are excellent model systems for addressing this paradigm as their fate can be redirected when discs regenerate after injury or when key selector genes are misregulated. Here, we show that when Polycomb expression is reduced, the wing selector gene vestigial is ectopically activated. This leads to the inappropriate formation of the Vestigial-Scalloped complex, which forces the eye to transform into a wing. We further demonstrate that disrupting this complex does not simply block wing formation or restore eye development. Instead, immunohistochemistry and high-throughput genomic analysis show that the eye-antennal disc unexpectedly undergoes hyperplastic growth with multiple domains being organized into other imaginal discs and tissues. These findings provide insight into the complex developmental landscape that tissues must navigate before adopting their final fate.
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Affiliation(s)
- Haley E. Brown
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | | | - Bonnie M. Weasner
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Justin P. Kumar
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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Brown HE, Weasner BP, Weasner BM, Kumar JP. Polycomb safeguards imaginal disc specification through control of the Vestigial-Scalloped complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536444. [PMID: 37090526 PMCID: PMC10120697 DOI: 10.1101/2023.04.11.536444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
A fundamental goal of developmental biology is to understand how cell and tissue fates are specified. The imaginal discs of Drosophila are excellent model systems for addressing this paradigm as their fate can be redirected when discs regenerate after injury or when key selector genes are mis-regulated. Here, we show that when Polycomb expression is reduced, the wing selector gene vestigial is ectopically activated. This leads to the inappropriate formation of the Vestigial-Scalloped complex which forces the eye to transform into a wing. We further demonstrate that disrupting this complex does not simply block wing formation or restore eye development. Instead, immunohistochemistry and high throughput genomic analysis show that the eye-antennal disc unexpectedly undergoes hyperplastic growth with multiple domains being organized into other imaginal discs and tissues. These findings provide insight into the complex developmental landscape that tissues must navigate before adopting their final fate. Summary Statement Here we describe a novel mechanism by which Pc promotes an eye fate during normal development and how the eye is reprogrammed into a wing in its absence.
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Affiliation(s)
- Haley E. Brown
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | | | - Bonnie M. Weasner
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Justin P. Kumar
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
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Zhang Y, Ma M, Liu M, Sun A, Zheng X, Liu K, Yin C, Li C, Jiang C, Tu X, Fang Y. Histone H2A monoubiquitination marks are targeted to specific sites by cohesin subunits in Arabidopsis. Nat Commun 2023; 14:1209. [PMID: 36869051 PMCID: PMC9984397 DOI: 10.1038/s41467-023-36788-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 02/16/2023] [Indexed: 03/05/2023] Open
Abstract
Histone H2A monoubiquitination (H2Aub1) functions as a conserved posttranslational modification in eukaryotes to maintain gene expression and guarantee cellular identity. Arabidopsis H2Aub1 is catalyzed by the core components AtRING1s and AtBMI1s of polycomb repressive complex 1 (PRC1). Because PRC1 components lack known DNA binding domains, it is unclear how H2Aub1 is established at specific genomic locations. Here, we show that the Arabidopsis cohesin subunits AtSYN4 and AtSCC3 interact with each other, and AtSCC3 binds to AtBMI1s. H2Aub1 levels are reduced in atsyn4 mutant or AtSCC3 artificial microRNA knockdown plants. ChIP-seq assays indicate that most binding events of AtSYN4 and AtSCC3 are associated with H2Aub1 along the genome where transcription is activated independently of H3K27me3. Finally, we show that AtSYN4 binds directly to the G-box motif and directs H2Aub1 to these sites. Our study thus reveals a mechanism for cohesin-mediated recruitment of AtBMI1s to specific genomic loci to mediate H2Aub1.
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Affiliation(s)
- Yu Zhang
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Min Ma
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Meng Liu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, 200065, Shanghai, China
| | - Aiqing Sun
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Xiaoyun Zheng
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Kunpeng Liu
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Chunmei Yin
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Chuanshun Li
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Cizhong Jiang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Life Sciences and Technology, Tongji University, 200065, Shanghai, China.
| | - Xiaoyu Tu
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China.
| | - Yuda Fang
- Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 200240, Shanghai, China.
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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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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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