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Kamalyan S, Kyrchanova O, Klimenko N, Babosha V, Vasileva Y, Belova E, Fursenko D, Maksimenko O, Georgiev P. The N-terminal dimerization domains of human and Drosophila CTCF have similar functionality. Epigenetics Chromatin 2024; 17:9. [PMID: 38561749 PMCID: PMC10983669 DOI: 10.1186/s13072-024-00534-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND CTCF is highly likely to be the ancestor of proteins that contain large clusters of C2H2 zinc finger domains, and its conservation is observed across most bilaterian organisms. In mammals, CTCF is the primary architectural protein involved in organizing chromosome topology and mediating enhancer-promoter interactions over long distances. In Drosophila, CTCF (dCTCF) cooperates with other architectural proteins to establish long-range interactions and chromatin boundaries. CTCFs of various organisms contain an unstructured N-terminal dimerization domain (DD) and clusters comprising eleven zinc-finger domains of the C2H2 type. The Drosophila (dCTCF) and human (hCTCF) CTCFs share sequence homology in only five C2H2 domains that specifically bind to a conserved 15 bp motif. RESULTS Previously, we demonstrated that CTCFs from different organisms carry unstructured N-terminal dimerization domains (DDs) that lack sequence homology. Here we used the CTCFattP(mCh) platform to introduce desired changes in the Drosophila CTCF gene and generated a series of transgenic lines expressing dCTCF with different variants of the N-terminal domain. Our findings revealed that the functionality of dCTCF is significantly affected by the deletion of the N-terminal DD. Additionally, we observed a strong impact on the binding of the dCTCF mutant to chromatin upon deletion of the DD. However, chromatin binding was restored in transgenic flies expressing a chimeric CTCF protein with the DD of hCTCF. Although the chimeric protein exhibited lower expression levels than those of the dCTCF variants, it efficiently bound to chromatin similarly to the wild type (wt) protein. CONCLUSIONS Our findings suggest that one of the evolutionarily conserved functions of the unstructured N-terminal dimerization domain is to recruit dCTCF to its genomic sites in vivo.
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Affiliation(s)
- Sofia Kamalyan
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St, Moscow, 119334, Russia
- Skolkovo Institute of Science and Technology, Moscow, 121205, Russia
| | - 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
| | - Valentin Babosha
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St, Moscow, 119334, Russia
| | - Yulia Vasileva
- 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
| | - Elena Belova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St, Moscow, 119334, Russia
| | - Dariya Fursenko
- 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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Kyrchanova O, Ibragimov A, Postika N, Georgiev P, Schedl P. Boundary bypass activity in the abdominal-B region of the Drosophila bithorax complex is position dependent and regulated. Open Biol 2023; 13:230035. [PMID: 37582404 PMCID: PMC10427195 DOI: 10.1098/rsob.230035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 07/17/2023] [Indexed: 08/17/2023] Open
Abstract
Expression of Abdominal-B (Abd-B) in abdominal segments A5-A8 is controlled by four regulatory domains, iab-5-iab-8. Each domain has an initiator element (which sets the activity state), elements that maintain this state and tissue-specific enhancers. To ensure their functional autonomy, each domain is bracketed by boundary elements (Mcp, Fab-7, Fab-7 and Fab-8). In addition to blocking crosstalk between adjacent regulatory domains, the Fab boundaries must also have bypass activity so the relevant regulatory domains can 'jump over' intervening boundaries and activate the Abd-B promoter. In the studies reported here we have investigated the parameters governing bypass activity. We find that the bypass elements in the Fab-7 and Fab-8 boundaries must be located in the regulatory domain that is responsible for driving Abd-B expression. We suggest that bypass activity may also be subject to regulation.
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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
| | - Airat Ibragimov
- 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
- Laboratory of Gene Expression Regulation in Development, 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
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Kyrchanova O, Ibragimov A, Postika N, Georgiev P, Schedl P. Boundary Bypass Activity in the Abdominal-B Region of the Drosophila Bithorax Complex is Position Dependent and Regulated. bioRxiv 2023:2023.06.06.543971. [PMID: 37333165 PMCID: PMC10274778 DOI: 10.1101/2023.06.06.543971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Expression of Abdominal-B ( Abd-B ) in abdominal segments A5 - A8 is controlled by four regulatory domains, iab-5 - iab-8 . Each domain has an initiator element (which sets the activity state), elements that maintain this state and tissue-specific enhancers. To ensure their functional autonomy, each domain is bracketed by boundary elements ( Mcp , Fab-7 , Fab-7 and Fab-8 ). In addition to blocking crosstalk between adjacent regulatory domains, the Fab boundaries must also have bypass activity so the relevant regulatory domains can "jump over" intervening boundaries and activate the Abd-B promoter. In the studies reported here we have investigated the parameters governing bypass activity. We find that the bypass elements in the Fab-7 and Fab-8 boundaries must be located in the regulatory domain that is responsible for driving Abd-B expression. We suggest that bypass activity may also be subject to regulation. Summary Statement Boundaries separating Abd-B regulatory domains block crosstalk between domains and mediate their interactions with Abd-B . The latter function is location but not orientation dependent.
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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
| | - Airat Ibragimov
- 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
- Laboratory of Gene Expression Regulation in Development, 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
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
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Kyrchanova O, Sokolov V, Tikhonov M, Schedl P, Georgiev P. Transcriptional read through interrupts boundary function in Drosophila. bioRxiv 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Postika N, Schedl P, Georgiev P, Kyrchanova O. Redundant enhancers in the iab-5 domain cooperatively activate Abd-B in the A5 and A6 abdominal segments of Drosophila. Development 2021; 148:272019. [PMID: 34473267 DOI: 10.1242/dev.199827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 08/21/2021] [Indexed: 01/10/2023]
Abstract
The Abdominal-B (Abd-B) gene belongs to the bithorax complex and its expression is controlled by four regulatory domains, iab-5, iab-6, iab-7 and iab-8, each of which is thought to be responsible for directing the expression of Abd-B in one of the abdominal segments from A5 to A8. A variety of experiments have supported the idea that BX-C regulatory domains are functionally autonomous and that each domain is both necessary and sufficient to orchestrate the development of the segment they specify. Unexpectedly, we discovered that this model does not always hold. Instead, we find that tissue-specific enhancers located in the iab-5 domain are required for the proper activation of Abd-B not only in A5 but also in A6. Our findings indicate that the functioning of the iab-5 and iab-6 domains in development of the adult cuticle A5 and A6 in males fit better with an additive model, much like that first envisioned by Ed Lewis.
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Affiliation(s)
- Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia.,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
| | - 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
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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. Biochim Biophys Acta Gene Regul Mech 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Postika N, Schedl P, Georgiev P, Kyrchanova O. Redundant enhancers in the iab-5 domain cooperatively activate Abd-B in the A5 and A6 abdominal segments of Drosophila.. [DOI: 10.1101/2021.05.22.445252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
AbstractThe homeotic Abdominal-B (Abd-B) gene belongs to Bithorax complex and is regulated by four regulatory domains named iab-5, iab-6, iab-7 and iab-8, each of which is thought to be responsible for directing the expression of Abd-B in one of the abdominal segments from A5 to A8. It is assumed that male specific features of the adult cuticle in A5 is solely dependent on regulatory elements located in iab-5, while the regulatory elements in the iab-6 are both necessary and sufficient for the proper differentiation of the A6 cuticle. Unexpectedly, we found that this long held assumption is not correct. Instead, redundant tissue-specific enhancers located in the iab-5 domain are required for the proper activation of Abd-B not only in A5 but also in A6. Our study of deletions shows that the iab-5 initiator is essential for the functioning of the iab-5 enhancers in A5, as well as for the correct differentiation of A6. This requirement is circumvented by deletions that remove the initiator and most of the iab-5 regulatory domain sequences. While the remaining iab-5 enhancers are inactive in A5, they are activated in A6 and contribute to the differentiation of this segment. In this case, Abd-B stimulation by the iab-5 enhancers in A6 depends on the initiators in the iab-4 and iab-6 domains.Summary StatementIn Drosophila, the segmental-specific expression of the homeotic gene Abdominal-B in the abdominal segments is regulated by autonomous regulatory domains. We demonstrated cooperation between these domains in activation of Abdominal-B.
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Sabirov M, Kyrchanova O, Pokholkova GV, Bonchuk A, Klimenko N, Belova E, Zhimulev IF, Maksimenko O, Georgiev P. Mechanism and functional role of the interaction between CP190 and the architectural protein Pita in Drosophila melanogaster. Epigenetics Chromatin 2021; 14:16. [PMID: 33752739 PMCID: PMC7983404 DOI: 10.1186/s13072-021-00391-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/08/2021] [Indexed: 12/16/2022] Open
Abstract
Background Pita is required for Drosophila development and binds specifically to a long motif in active promoters and insulators. Pita belongs to the Drosophila family of zinc-finger architectural proteins, which also includes Su(Hw) and the conserved among higher eukaryotes CTCF. The architectural proteins maintain the active state of regulatory elements and the long-distance interactions between them. In particular, Pita is involved in the formation of several boundaries between regulatory domains that controlled the expression of three hox genes in the Bithorax complex (BX-C). The CP190 protein is recruited to chromatin through interaction with the architectural proteins. Results Using in vitro pull-down analysis, we precisely mapped two unstructured regions of Pita that interact with the BTB domain of CP190. Then we constructed transgenic lines expressing the Pita protein of the wild-type and mutant variants lacking CP190-interacting regions. We have demonstrated that CP190-interacting region of the Pita can maintain nucleosome-free open chromatin and is critical for Pita-mediated enhancer blocking activity in BX-C. At the same time, interaction with CP190 is not required for the in vivo function of the mutant Pita protein, which binds to the same regions of the genome as the wild-type protein. Unexpectedly, we found that CP190 was still associated with the most of genome regions bound by the mutant Pita protein, which suggested that other architectural proteins were continuing to recruit CP190 to these regions. Conclusions The results directly demonstrate role of CP190 in insulation and support a model in which the regulatory elements are composed of combinations of binding sites that interact with several architectural proteins with similar functions. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00391-x.
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Affiliation(s)
- Marat Sabirov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 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
| | - Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 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
| | - Galina V Pokholkova
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, Russia
| | - Artem Bonchuk
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 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
| | - Elena Belova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 3 4/5 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
| | - Igor F Zhimulev
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB RAS), Novosibirsk, 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, 3 4/5 Vavilov St., Moscow, 119334, Russia.
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Postika N, Schedl P, Georgiev P, Kyrchanova O. Mapping of functional elements of the Fab-6 boundary involved in the regulation of the Abd-B hox gene in Drosophila melanogaster. Sci Rep 2021; 11:4156. [PMID: 33603202 PMCID: PMC7892861 DOI: 10.1038/s41598-021-83734-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
The autonomy of segment-specific regulatory domains in the Bithorax complex is conferred by boundary elements and associated Polycomb response elements (PREs). The Fab-6 boundary is located at the junction of the iab-5 and iab-6 domains. Previous studies mapped it to a nuclease hypersensitive region 1 (HS1), while the iab-6 PRE was mapped to a second hypersensitive region HS2 nearly 3 kb away. To analyze the role of HS1 and HS2 in boundary we generated deletions of HS1 or HS1 + HS2 that have attP site for boundary replacement experiments. The 1389 bp HS1 deletion can be rescued by a 529 bp core Fab-6 sequence that includes two CTCF sites. However, Fab-6 HS1 cannot rescue the HS1 + HS2 deletion or substitute for another BX-C boundary - Fab-7. For this it must be combined with a PRE, either Fab-7 HS3, or Fab-6 HS2. These findings suggest that the boundary function of Fab-6 HS1 must be bolstered by a second element that has PRE activity.
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Affiliation(s)
- Nikolay Postika
- grid.419021.f0000 0004 0380 8267Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow, Russia 119334
| | - Paul Schedl
- grid.419021.f0000 0004 0380 8267Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow, Russia 119334 ,grid.16750.350000 0001 2097 5006Department of Molecular Biology, Princeton University, Princeton, NJ 08544 USA
| | - Pavel Georgiev
- grid.419021.f0000 0004 0380 8267Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow, Russia 119334
| | - Olga Kyrchanova
- grid.419021.f0000 0004 0380 8267Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow, Russia 119334 ,grid.419021.f0000 0004 0380 8267Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow, Russia 119334
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Kyrchanova O, Georgiev P. Mechanisms of Enhancer-Promoter Interactions in Higher Eukaryotes. Int J Mol Sci 2021; 22:ijms22020671. [PMID: 33445415 PMCID: PMC7828040 DOI: 10.3390/ijms22020671] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 12/28/2020] [Accepted: 01/09/2021] [Indexed: 12/13/2022] Open
Abstract
In higher eukaryotes, enhancers determine the activation of developmental gene transcription in specific cell types and stages of embryogenesis. Enhancers transform the signals produced by various transcription factors within a given cell, activating the transcription of the targeted genes. Often, developmental genes can be associated with dozens of enhancers, some of which are located at large distances from the promoters that they regulate. Currently, the mechanisms underlying specific distance interactions between enhancers and promoters remain poorly understood. This review briefly describes the properties of enhancers and discusses the mechanisms of distance interactions and potential proteins involved in this process.
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12
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Postika N, Schedl P, Georgiev P, Kyrchanova O. Mapping of functional elements of the Fab-6 boundary involved in the regulation of the Abd-B hox gene in Drosophila melanogaster.. [DOI: 10.21203/rs.3.rs-121843/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstract
The autonomy of segment-specific regulatory domains in the Bithorax complex is conferred by boundary elements and associated Polycomb response elements (PREs). The Fab-6 boundary is located at the junction of the iab-5 and iab-6 domains. Previous studies mapped it to a nuclease hypersensitive region 1 (HS1), while the iab-6 PRE was mapped to a second hypersensitive region HS2 nearly 3 kb away. To analyze the role of HS1 and HS2 in boundary we generated deletions of HS1 or HS1 + HS2 that have attP site for boundary replacement experiments. The 1389 bp HS1 deletion can be rescued by a 529 bp core Fab-6 sequence that includes two CTCF sites. However, Fab-6 HS1 cannot rescue the HS1 + HS2 deletion or substitute for another BX-C boundary – Fab-7. For this it must be combined with a PRE, either Fab-7 HS3, or Fab-6 HS2. These findings suggest that the boundary function of Fab-6 HS1 must be bolstered by an element that has PRE activity.
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13
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Kyrchanova O, Maksimenko O, Ibragimov A, Sokolov V, Postika N, Lukyanova M, Schedl P, Georgiev P. The insulator functions of the Drosophila polydactyl C2H2 zinc finger protein CTCF: Necessity versus sufficiency. Sci Adv 2020; 6:eaaz3152. [PMID: 32232161 PMCID: PMC7096168 DOI: 10.1126/sciadv.aaz3152] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/03/2020] [Indexed: 06/10/2023]
Abstract
In mammals, a C2H2 zinc finger (C2H2) protein, CTCF, acts as the master regulator of chromosomal architecture and of the expression of Hox gene clusters. Like mammalian CTCF, the Drosophila homolog, dCTCF, localizes to boundaries in the bithorax complex (BX-C). Here, we have determined the minimal requirements for the assembly of a functional boundary by dCTCF and two other C2H2 zinc finger proteins, Pita and Su(Hw). Although binding sites for these proteins are essential for the insulator activity of BX-C boundaries, these binding sites alone are insufficient to create a functional boundary. dCTCF cannot effectively bind to a single recognition sequence in chromatin or generate a functional insulator without the help of additional proteins. In addition, for boundary elements in BX-C at least four binding sites for dCTCF or the presence of additional DNA binding factors is required to generate a functional insulator.
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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
| | - 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
| | - Airat Ibragimov
- 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
| | - Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Maria Lukyanova
- Department of the Control of Genetic Processes, 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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Kyrchanova O, Wolle D, Sabirov M, Kurbidaeva A, Aoki T, Maksimenko O, Kyrchanova M, Georgiev P, Schedl P. Distinct Elements Confer the Blocking and Bypass Functions of the Bithorax Fab-8 Boundary. Genetics 2019; 213:865-876. [PMID: 31551239 PMCID: PMC6827379 DOI: 10.1534/genetics.119.302694] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 09/12/2019] [Indexed: 01/05/2023] Open
Abstract
Boundaries in the Drosophila bithorax complex (BX-C) enable the regulatory domains that drive parasegment-specific expression of the three Hox genes to function autonomously. The four regulatory domains (iab-5, iab-6, iab-7, and iab-8) that control the expression of the Abdominal-B (Abd-B) gene are located downstream of the transcription unit, and are delimited by the Mcp, Fab-6, Fab-7, and Fab-8 boundaries. These boundaries function to block cross talk between neighboring regulatory domains. In addition, three of the boundaries (Fab-6, Fab-7, and Fab-8) must also have bypass activity so that regulatory domains distal to the boundaries can contact the Abd-B promoter. In the studies reported here, we have undertaken a functional dissection of the Fab-8 boundary using a boundary-replacement strategy. Our studies indicate that the Fab-8 boundary has two separable subelements. The distal subelement blocks cross talk, but cannot support bypass. The proximal subelement has only minimal blocking activity but is able to mediate bypass. A large multiprotein complex, the LBC (large boundary complex), binds to sequences in the proximal subelement and contributes to its bypass activity. The same LBC complex has been implicated in the bypass activity of the Fab-7 boundary.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow 119334, Russia
| | - Daniel Wolle
- Department of Molecular Biology, Princeton University, New Jersey 08544
| | - Marat Sabirov
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow 119334, Russia
| | - Amina Kurbidaeva
- Department of Molecular Biology, Princeton University, New Jersey 08544
| | - Tsutomu Aoki
- Department of Molecular Biology, Princeton University, New Jersey 08544
| | - Oksana Maksimenko
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow 119334, Russia
| | - Maria Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow 119334, Russia
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, New Jersey 08544
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, Moscow 119334, Russia
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15
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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16
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Kyrchanova O, Kurbidaeva A, Sabirov M, Postika N, Wolle D, Aoki T, Maksimenko O, Mogila V, Schedl P, Georgiev P. The bithorax complex iab-7 Polycomb response element has a novel role in the functioning of the Fab-7 chromatin boundary. PLoS Genet 2018; 14:e1007442. [PMID: 30110328 PMCID: PMC6110506 DOI: 10.1371/journal.pgen.1007442] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/27/2018] [Accepted: 07/30/2018] [Indexed: 12/22/2022] Open
Abstract
Expression of the three bithorax complex homeotic genes is orchestrated by nine parasegment-specific regulatory domains. Autonomy of each domain is conferred by boundary elements (insulators). Here, we have used an in situ replacement strategy to reanalyze the sequences required for the functioning of one of the best-characterized fly boundaries, Fab-7. It was initially identified by a deletion, Fab-71, that transformed parasegment (PS) 11 into a duplicate copy of PS12. Fab-71 deleted four nuclease hypersensitive sites, HS*, HS1, HS2, and HS3, located between the iab-6 and iab-7 regulatory domains. Transgenic and P-element excision experiments mapped the boundary to HS*+HS1+HS2, while HS3 was shown to be the iab-7 Polycomb response element (PRE). Recent replacement experiments showed that HS1 is both necessary and sufficient for boundary activity when HS3 is also present in the replacement construct. Surprisingly, while HS1+HS3 combination has full boundary activity, we discovered that HS1 alone has only minimal function. Moreover, when combined with HS3, only the distal half of HS1, dHS1, is needed. A ~1,000 kD multiprotein complex containing the GAF protein, called the LBC, binds to the dHS1 sequence and we show that mutations in dHS1, that disrupt LBC binding in nuclear extracts, eliminate boundary activity and GAF binding in vivo. HS3 has binding sites for GAF and Pho proteins that are required for PRE silencing. In contrast, HS3 boundary activity only requires the GAF binding sites. LBC binding with HS3 in nuclear extracts, and GAF association in vivo, depend upon the HS3 GAF sites, but not the Pho sites. Consistent with a role for the LBC in HS3 boundary activity, the boundary function of the dHS1+HS3mPho combination is lost when the flies are heterozygous for a mutation in the GAF gene. Taken together, these results reveal a novel function for the iab-7 PREs in chromosome architecture. Polycomb group proteins (PcG) are important epigenetic regulators of developmental genes in all higher eukaryotes. In Drosophila, these proteins are bound to specific regulatory DNA elements called Polycomb group Response Elements (PREs). Drosophila PREs are made up of binding sites for a complex array of DNA binding proteins, including GAF and Pho. In the regulatory region of the bithorax complex (BX-C), the boundary/insulator elements organize the autonomous regulatory domains, and their active or repressed states are regulated by PREs. Here, we studied functional properties of sequences that constitute the Fab-7 boundary and the adjacent iab-7 PRE. It was previously thought that the sole function of the iab-7 PRE is to recruit PcG proteins in parasegments anterior to PS12 and silence the iab-7 domain. However, we found that the iab-7 PRE also functions as a component of the Fab-7 boundary. The boundary activity of the iab-7 PRE sequence depends upon a large complex called the LBC. We show that it is possible to reconstitute a fully functional boundary by combining the LBC binding sequences in HS1 with the iab-7 PRE. Moreover, its boundary function is independent of its PcG silencing activity.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Amina Kurbidaeva
- 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, United States of America
| | - Marat Sabirov
- Group of Molecular Organization of Genome, Institute of Gene Biology, Russian Acsademy of Sciences, Moscow, Russia
| | - Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Daniel Wolle
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States of America
| | - Tsutomu Aoki
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States of America
| | - Oksana Maksimenko
- Group of Molecular Organization of Genome, Institute of Gene Biology, Russian Acsademy of Sciences, Moscow, Russia
| | - Vladic Mogila
- Laboratory of Gene Expression Regulation in Development, 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, United States of America
- * E-mail: (PS); (PG)
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail: (PS); (PG)
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17
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Zolotarev N, Maksimenko O, Kyrchanova O, Sokolinskaya E, Osadchiy I, Girardot C, Bonchuk A, Ciglar L, Furlong EEM, Georgiev P. Opbp is a new architectural/insulator protein required for ribosomal gene expression. Nucleic Acids Res 2017; 45:12285-12300. [PMID: 29036346 PMCID: PMC5716193 DOI: 10.1093/nar/gkx840] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/14/2017] [Indexed: 12/22/2022] Open
Abstract
A special class of poorly characterized architectural proteins is required for chromatin topology and enhancer–promoter interactions. Here, we identify Opbp as a new Drosophila architectural protein, interacting with CP190 both in vivo and in vitro. Opbp binds to a very restrictive set of genomic regions, through a rare sequence specific motif. These sites are co-bound by CP190 in vivo, and generally located at bidirectional promoters of ribosomal protein genes. We show that Opbp is essential for viability, and loss of opbp function, or destruction of its motif, leads to reduced ribosomal protein gene expression, indicating a functional role in promoter activation. As characteristic of architectural/insulator proteins, the Opbp motif is sufficient for distance-dependent reporter gene activation and enhancer-blocking activity, suggesting an Opbp-mediated enhancer–promoter interaction. Rather than having a constitutive role, Opbp represents a new type of architectural protein with a very restricted, yet essential, function in regulation of housekeeping gene expression.
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Affiliation(s)
- Nikolay Zolotarev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Oksana Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Olga Kyrchanova
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Elena Sokolinskaya
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119234, Russia
| | - Igor Osadchiy
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Charles Girardot
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Artem Bonchuk
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
| | - Lucia Ciglar
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Pavel Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilova St., Moscow 119334, Russia
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18
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Kyrchanova O, Zolotarev N, Mogila V, Maksimenko O, Schedl P, Georgiev P. Architectural protein Pita cooperates with dCTCF in organization of functional boundaries in Bithorax complex. Development 2017; 144:2663-2672. [PMID: 28619827 DOI: 10.1242/dev.149815] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/08/2017] [Indexed: 12/11/2022]
Abstract
Boundaries in the Bithorax complex (BX-C) of Drosophila delimit autonomous regulatory domains that drive parasegment-specific expression of homeotic genes. BX-C boundaries have two crucial functions: they must block crosstalk between adjacent regulatory domains and at the same time facilitate boundary bypass. The C2H2 zinc-finger protein Pita binds to several BX-C boundaries, including Fab-7 and Mcp To study Pita functions, we have used a boundary replacement strategy by substituting modified DNAs for the Fab-7 boundary, which is located between the iab-6 and iab-7 regulatory domains. Multimerized Pita sites block iab-6↔iab-7 crosstalk but fail to support iab-6 regulation of Abd-B (bypass). In the case of Fab-7, we used a novel sensitized background to show that the two Pita-binding sites contribute to its boundary function. Although Mcp is from BX-C, it does not function appropriately when substituted for Fab-7: it blocks crosstalk but does not support bypass. Mutation of the Mcp Pita site disrupts blocking activity and also eliminates dCTCF binding. In contrast, mutation of the Mcp dCTCF site does not affect Pita binding, and this mutant boundary retains partial function.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Nikolay Zolotarev
- Group of Molecular Organization of Genome, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Vladic Mogila
- Laboratory of Regulation of Gene Expression in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Oksana Maksimenko
- Group of Molecular Organization of Genome, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Paul Schedl
- Laboratory of Regulation of Gene Expression in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia .,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, Moscow 119334, Russia
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19
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Kyrchanova O, Mogila V, Wolle D, Deshpande G, Parshikov A, Cléard F, Karch F, Schedl P, Georgiev P. Functional Dissection of the Blocking and Bypass Activities of the Fab-8 Boundary in the Drosophila Bithorax Complex. PLoS Genet 2016; 12:e1006188. [PMID: 27428541 PMCID: PMC4948906 DOI: 10.1371/journal.pgen.1006188] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 06/22/2016] [Indexed: 12/16/2022] Open
Abstract
Functionally autonomous regulatory domains direct the parasegment-specific expression of the Drosophila Bithorax complex (BX-C) homeotic genes. Autonomy is conferred by boundary/insulator elements that separate each regulatory domain from its neighbors. For six of the nine parasegment (PS) regulatory domains in the complex, at least one boundary is located between the domain and its target homeotic gene. Consequently, BX-C boundaries must not only block adventitious interactions between neighboring regulatory domains, but also be permissive (bypass) for regulatory interactions between the domains and their gene targets. To elucidate how the BX-C boundaries combine these two contradictory activities, we have used a boundary replacement strategy. We show that a 337 bp fragment spanning the Fab-8 boundary nuclease hypersensitive site and lacking all but 83 bp of the 625 bp Fab-8 PTS (promoter targeting sequence) fully rescues a Fab-7 deletion. It blocks crosstalk between the iab-6 and iab-7 regulatory domains, and has bypass activity that enables the two downstream domains, iab-5 and iab-6, to regulate Abdominal-B (Abd-B) transcription in spite of two intervening boundary elements. Fab-8 has two dCTCF sites and we show that they are necessary both for blocking and bypass activity. However, CTCF sites on their own are not sufficient for bypass. While multimerized dCTCF (or Su(Hw)) sites have blocking activity, they fail to support bypass. Moreover, this bypass defect is not rescued by the full length PTS. Finally, we show that orientation is critical for the proper functioning the Fab-8 replacement. Though the inverted Fab-8 boundary still blocks crosstalk, it disrupts the topology of the Abd-B regulatory domains and does not support bypass. Importantly, altering the orientation of the Fab-8 dCTCF sites is not sufficient to disrupt bypass, indicating that orientation dependence is conferred by other factors. Boundary elements in the Bithorax complex have two seemingly contradictory activities. They must block crosstalk between neighboring regulatory domains, but at the same time be permissive (insulator bypass) for regulatory interactions between the domains and the BX-C homeotic genes. We have used a replacement strategy to investigate how they carry out these two functions. We show that a 337 bp fragment spanning the Fab-8 boundary nuclease hypersensitive site is sufficient to fully rescue a Fab-7 boundary deletion. It blocks crosstalk and supports bypass. As has been observed in transgene assays, blocking activity requires the Fab-8 dCTCF sites, while full bypass activity requires the dCTCF sites plus a small part of PTS. In transgene assays, bypass activity typically depends on the orientation of the two insulators relative to each other. A similar orientation dependence is observed for the Fab-8 replacement in BX-C. When the orientation of the Fab-8 boundary is reversed, bypass activity is lost, while blocking is unaffected. Interestingly, unlike what has been observed in mammals, reversing the orientation of only the Fab-8 dCTCF sites does not affect boundary function. This finding indicates that other Fab-8 factors must play a critical role in determining orientation. Taken together, our findings argue that carrying out the paradoxical functions of the BX-C boundaries does not require any unusual or special properties; rather BX-C boundaries utilize generic blocking and insulator bypass activities that are appropriately adapted to their regulatory context. Thus making them a good model for studying the functional properties of boundaries/insulators in their native setting.
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Affiliation(s)
- Olga Kyrchanova
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail: (OK); (PG)
| | - Vladic Mogila
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Daniel Wolle
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Alexander Parshikov
- Department of Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Fabienne Cléard
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Francois Karch
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Paul Schedl
- Department of Genetics, 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 Genetics, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail: (OK); (PG)
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Zolotarev N, Fedotova A, Kyrchanova O, Bonchuk A, Penin AA, Lando AS, Eliseeva IA, Kulakovskiy IV, Maksimenko O, Georgiev P. Architectural proteins Pita, Zw5,and ZIPIC contain homodimerization domain and support specific long-range interactions in Drosophila. Nucleic Acids Res 2016; 44:7228-41. [PMID: 27137890 PMCID: PMC5009728 DOI: 10.1093/nar/gkw371] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/23/2016] [Indexed: 12/18/2022] Open
Abstract
According to recent models, as yet poorly studied architectural proteins appear to be required for local regulation of enhancer-promoter interactions, as well as for global chromosome organization. Transcription factors ZIPIC, Pita and Zw5 belong to the class of chromatin insulator proteins and preferentially bind to promoters near the TSS and extensively colocalize with cohesin and condensin complexes. ZIPIC, Pita and Zw5 are structurally similar in containing the N-terminal zinc finger-associated domain (ZAD) and different numbers of C2H2-type zinc fingers at the C-terminus. Here we have shown that the ZAD domains of ZIPIC, Pita and Zw5 form homodimers. In Drosophila transgenic lines, these proteins are able to support long-distance interaction between GAL4 activator and the reporter gene promoter. However, no functional interaction between binding sites for different proteins has been revealed, suggesting that such interactions are highly specific. ZIPIC facilitates long-distance stimulation of the reporter gene by GAL4 activator in yeast model system. Many of the genomic binding sites of ZIPIC, Pita and Zw5 are located at the boundaries of topologically associated domains (TADs). Thus, ZAD-containing zinc-finger proteins can be attributed to the class of architectural proteins.
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Affiliation(s)
- Nikolay Zolotarev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Anna Fedotova
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Olga Kyrchanova
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Artem Bonchuk
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Aleksey A Penin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119991, Russia; Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127051 Russia; Department of Genetics, Faculty of Biology, Moscow State University, Moscow 119991, Russia
| | - Andrey S Lando
- Moscow Institute of Physics and Technology (State University), Institutskiy per. 9, Dolgoprudny, Moscow Region 141700, Russia Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, Moscow, GSP-1, 119991, Russia
| | - Irina A Eliseeva
- Group of Protein Biosynthesis Regulation, Institute of Protein Research, Institutskaya str. 4, Pushchino 142290, Russia
| | - Ivan V Kulakovskiy
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina str. 3, Moscow, GSP-1, 119991, Russia Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova str. 32, Moscow, GSP-1, 119991, Russia
| | - Oksana Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
| | - Pavel Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, Moscow 119334, Russia
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21
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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: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Maksimenko O, Bartkuhn M, Stakhov V, Herold M, Zolotarev N, Jox T, Buxa MK, Kirsch R, Bonchuk A, Fedotova A, Kyrchanova O, Renkawitz R, Georgiev P. Two new insulator proteins, Pita and ZIPIC, target CP190 to chromatin. Genome Res 2014; 25:89-99. [PMID: 25342723 PMCID: PMC4317163 DOI: 10.1101/gr.174169.114] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Insulators are multiprotein-DNA complexes that regulate the nuclear architecture. The Drosophila CP190 protein is a cofactor for the DNA-binding insulator proteins Su(Hw), CTCF, and BEAF-32. The fact that CP190 has been found at genomic sites devoid of either of the known insulator factors has until now been unexplained. We have identified two DNA-binding zinc-finger proteins, Pita, and a new factor named ZIPIC, that interact with CP190 in vivo and in vitro at specific interaction domains. Genomic binding sites for these proteins are clustered with CP190 as well as with CTCF and BEAF-32. Model binding sites for Pita or ZIPIC demonstrate a partial enhancer-blocking activity and protect gene expression from PRE-mediated silencing. The function of the CTCF-bound MCP insulator sequence requires binding of Pita. These results identify two new insulator proteins and emphasize the unifying function of CP190, which can be recruited by many DNA-binding insulator proteins.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Marek Bartkuhn
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Viacheslav Stakhov
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Martin Herold
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Nickolay Zolotarev
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Theresa Jox
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Melanie K Buxa
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Ramona Kirsch
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany
| | - Artem Bonchuk
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Anna Fedotova
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Olga Kyrchanova
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Rainer Renkawitz
- Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany;
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
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23
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Maksimenko O, Kyrchanova O, Bonchuk A, Stakhov V, Parshikov A, Georgiev P. Highly conserved ENY2/Sus1 protein binds to Drosophila CTCF and is required for barrier activity. Epigenetics 2014; 9:1261-70. [PMID: 25147918 DOI: 10.4161/epi.32086] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chromatin insulators affect interactions between promoters and enhancers/silencers and function as barriers for the spreading of repressive chromatin. Drosophila insulator protein dCTCF marks active promoters and boundaries of many histone H3K27 trimethylation domains associated with repressed chromatin. In particular, dCTCF binds to such boundaries between the parasegment-specific regulatory domains of the Bithorax complex. Here we demonstrate that the evolutionarily conserved protein ENY2 is recruited to the zinc-finger domain of dCTCF and is required for the barrier activity of dCTCF-dependent insulators in transgenic lines. Inactivation of ENY2 by RNAi in BG3 cells leads to the spreading of H3K27 trimethylation and Pc protein at several dCTCF boundaries. The results suggest that evolutionarily conserved ENY2 is responsible for barrier activity mediated by the dCTCF protein.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Olga Kyrchanova
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Artem Bonchuk
- Group of Transcriptional Regulation; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Viacheslav Stakhov
- Laboratory of Gene Expression Regulation in Development; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Alexander Parshikov
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes; Institute of Gene Biology; Russian Academy of Sciences; Moscow, Russia
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24
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Kyrchanova O, Georgiev P. Chromatin insulators and long-distance interactions in Drosophila. FEBS Lett 2013; 588:8-14. [PMID: 24211836 DOI: 10.1016/j.febslet.2013.10.039] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 10/25/2013] [Accepted: 10/25/2013] [Indexed: 12/31/2022]
Abstract
Data on long-distance enhancer-mediated activation of gene promoters and complex regulation of gene expression by multiple enhancers have prompted the hypothesis that the action of enhancers is restricted by insulators. Studies with transgenic lines have shown that insulators are responsible for establishing proper local interactions between regulatory elements, but not for defining independent transcriptional domains that restrict the activity of enhancers. It has also become apparent that enhancer blocking is only one of several functional activities of known insulator proteins, which also contribute to the organization of chromosome architecture and the integrity of regulatory elements.
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Affiliation(s)
- Olga Kyrchanova
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, 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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25
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Kyrchanova O, Leman D, Parshikov A, Fedotova A, Studitsky V, Maksimenko O, Georgiev P. New properties of Drosophila scs and scs' insulators. PLoS One 2013; 8:e62690. [PMID: 23638134 PMCID: PMC3634774 DOI: 10.1371/journal.pone.0062690] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 03/25/2013] [Indexed: 11/18/2022] Open
Abstract
Insulators are defined as a class of regulatory elements that delimit independent transcriptional domains within eukaryotic genomes. The first insulators to be identified were scs and scs', which flank the domain including two heat shock 70 genes. Zw5 and BEAF bind to scs and scs', respectively, and are responsible for the interaction between these insulators. Using the regulatory regions of yellow and white reporter genes, we have found that the interaction between scs and scs' improves the enhancer-blocking activity of the weak scs' insulator. The sequences of scs and scs' insulators include the promoters of genes that are strongly active in S2 cells but not in the eyes, in which the enhancer-blocking activity of these insulators has been extensively examined. Only the promoter of the Cad87A gene located at the end of the scs insulator drives white expression in the eyes, and the white enhancer can slightly stimulate this promoter. The scs insulator contains polyadenylation signals that may be important for preventing transcription through the insulator. As shown previously, scs and scs' can insulate transcription of the white transgene from the enhancing effects of the surrounding genome, a phenomenon known as the chromosomal position effect (CPE). After analyzing many independent transgenic lines, we have concluded that transgenes carrying the scs insulator are rarely inserted into genomic regions that stimulate the white reporter expression in the eyes.
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Affiliation(s)
- Olga Kyrchanova
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Dmitry Leman
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Alexander Parshikov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Anna Fedotova
- Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Vasily Studitsky
- School of Biology, Moscow State University, Moscow, Russia
- Department of Pharmacology, UMDNJ–Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Oksana Maksimenko
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- * E-mail:
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26
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Erokhin M, Davydova A, Kyrchanova O, Parshikov A, Georgiev P, Chetverina D. Insulators form gene loops by interacting with promoters in Drosophila. Development 2011; 138:4097-106. [PMID: 21862564 DOI: 10.1242/dev.062836] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chromatin insulators are regulatory elements involved in the modulation of enhancer-promoter communication. The 1A2 and Wari insulators are located immediately downstream of the Drosophila yellow and white genes, respectively. Using an assay based on the yeast GAL4 activator, we have found that both insulators are able to interact with their target promoters in transgenic lines, forming gene loops. The existence of an insulator-promoter loop is confirmed by the fact that insulator proteins could be detected on the promoter only in the presence of an insulator in the transgene. The upstream promoter regions, which are required for long-distance stimulation by enhancers, are not essential for promoter-insulator interactions. Both insulators support basal activity of the yellow and white promoters in eyes. Thus, the ability of insulators to interact with promoters might play an important role in the regulation of basal gene transcription.
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Affiliation(s)
- Maksim Erokhin
- 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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27
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Kyrchanova O, Ivlieva T, Toshchakov S, Parshikov A, Maksimenko O, Georgiev P. Selective interactions of boundaries with upstream region of Abd-B promoter in Drosophila bithorax complex and role of dCTCF in this process. Nucleic Acids Res 2010; 39:3042-52. [PMID: 21149269 PMCID: PMC3082887 DOI: 10.1093/nar/gkq1248] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Expression of the genes Ubx, abd-A, and Abd-B of the bithorax complex depends on its cis-regulatory region, which is divided into discrete functional domains (iab). Boundary/insulator elements, named Mcp, Fab-6, Fab-7 and Fab-8 (PTS/F8), have been identified at the borders of the iab domains. Recently, binding sites for a Drosophila homolog of the vertebrate insulator protein CTCF have been identified in Mcp, Fab-6 and Fab-8 and also in several regions that correspond to predicted boundaries, Fab-3 and Fab-4 in particular. Taking into account the inability of the yeast GAL4 activator to stimulate the white promoter when the activator and the promoter are separated by a 5-kb yellow gene, we have tested functional interactions between the boundaries. The results show that all dCTCF-containing boundaries interact with each other. However, inactivation of dCTCF binding sites in Mcp, Fab-6 and PTS/F8 only partially reduces their ability to interact, suggesting the presence of additional protein(s) supporting distant interactions between the boundaries. Interestingly, only Fab-6, Fab-7 (which contains no dCTCF binding sites) and PTS/F8 interact with the upstream region of the Abd-B promoter. Thus, the boundaries might be involved in supporting the specific interactions between iab enhancers and promoters of the bithorax complex.
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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
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28
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Kyrchanova O, Chetverina D, Maksimenko O, Kullyev A, Georgiev P. Orientation-dependent interaction between Drosophila insulators is a property of this class of regulatory elements. Nucleic Acids Res 2008; 36:7019-28. [PMID: 18987002 PMCID: PMC2602758 DOI: 10.1093/nar/gkn781] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Insulators are defined as a class of regulatory elements that delimit independent transcriptional domains within eukaryotic genomes. According to previous data, an interaction (pairing) between some Drosophila insulators can support distant activation of a promoter by an enhancer. Here, we have demonstrated that pairs of well-studied insulators such as scs-scs, scs'-scs', 1A2-1A2 and Wari-Wari support distant activation of the white promoter by the yeast GAL4 activator in an orientation-dependent manner. The same is true for the efficiency of the enhancer that stimulates white expression in the eyes. In all insulator pairs tested, stimulation of the white gene was stronger when insulators were inserted between the eye enhancer or GAL4 and the white promoter in opposite orientations relative to each other. As shown previously, Zw5, Su(Hw) and dCTCF proteins are required for the functioning of different insulators that do not interact with each other. Here, strong functional interactions have been revealed between DNA fragments containing binding sites for either Zw5 or Su(Hw) or dCTCF protein but not between heterologous binding sites [Zw5-Su(Hw), dCTCF-Su(Hw), or dCTCF-Zw5]. These results suggest that insulator proteins can support selective interactions between distant regulatory elements.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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29
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Kyrchanova O, Toshchakov S, Podstreshnaya Y, Parshikov A, Georgiev P. Functional interaction between the Fab-7 and Fab-8 boundaries and the upstream promoter region in the Drosophila Abd-B gene. Mol Cell Biol 2008; 28:4188-95. [PMID: 18426914 PMCID: PMC2423118 DOI: 10.1128/mcb.00229-08] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 04/05/2008] [Indexed: 11/20/2022] Open
Abstract
Boundary elements have been found in the regulatory region of the Drosophila melanogaster Abdominal-B (Abd-B) gene, which is subdivided into a series of iab domains. The best-studied Fab-7 and Fab-8 boundaries flank the iab-7 enhancer and isolate it from the four promoters regulating Abd-B expression. Recently binding sites for the Drosophila homolog of the vertebrate insulator protein CTCF (dCTCF) were identified in the Fab-8 boundary and upstream of Abd-B promoter A, with no binding of CTCF to the Fab-7 boundary being detected either in vivo or in vitro. Taking into account the inability of the yeast GAL4 activator to stimulate the white promoter when its binding sites are separated by a 5-kb yellow gene, we have tested the functional interactions between the Fab-7 and Fab-8 boundaries and between these boundaries and the upstream promoter A region containing a dCTCF binding site. It has been found that dCTCF binding sites are essential for pairing between two Fab-8 insulators. However, a strong functional interaction between the Fab-7 and Fab-8 boundaries suggests that additional, as yet unidentified proteins are involved in long-distance interactions between them. We have also shown that Fab-7 and Fab-8 boundaries effectively interact with the upstream region of the Abd-B promoter.
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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
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30
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Abstract
In the Abd-B 3' cis-regulatory region, which is subdivided into a series of iab domains, boundary elements have previously been detected, including the Fab-7 element providing for the autonomous functioning of the iab-6 and iab-7 cis-regulatory domains. Here, it has been shown that a single copy of the 860-bp Fab-7 insulator effectively blocks the yellow and white enhancers. The eye and testis enhancers can stimulate the white promoter across the pair of Fab-7, which is indicative of a functional interaction between the insulators. Unexpectedly, Fab-7 has proved to lose the enhancer-blocking activity when placed near the white promoter. It seems likely that Fab-7 strengthens the relatively weak white promoter, which leads to the efficient enhancer-promoter interaction and insulator bypass.
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Affiliation(s)
- Sergey Rodin
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
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31
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Kyrchanova O, Toshchakov S, Parshikov A, Georgiev P. Study of the functional interaction between Mcp insulators from the Drosophila bithorax complex: effects of insulator pairing on enhancer-promoter communication. Mol Cell Biol 2007; 27:3035-43. [PMID: 17283051 PMCID: PMC1899939 DOI: 10.1128/mcb.02203-06] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Boundary elements have been found in the Abd-B 3' cis-regulatory region, which is subdivided into a series of iab domains. Previously, a 340-bp insulator-like element, M(340), was identified in one such 755-bp Mcp fragment linked to the PcG-dependent silencer. In this study, we identified a 210-bp core that was sufficient for pairing of sequence-remote Mcp elements. In two-gene transgenic constructs with two Mcp insulators (or their cores) surrounding yellow, the upstream yeast GAL4 sites were able to activate the distal white only if the insulators were in the opposite orientations (head-to-head or tail-to-tail), which is consistent with the looping/bypass model. The same was true for the efficiency of the cognate eye enhancer, while yellow thus isolated in the loop from its enhancers was blocked more strongly. These results indicate that the relative placement and orientation of insulator-like elements can determine proper enhancer-promoter communication.
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Affiliation(s)
- Olga Kyrchanova
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
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32
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Gruzdeva N, Kyrchanova O, Parshikov A, Kullyev A, Georgiev P. The Mcp element from the bithorax complex contains an insulator that is capable of pairwise interactions and can facilitate enhancer-promoter communication. Mol Cell Biol 2005; 25:3682-9. [PMID: 15831473 PMCID: PMC1084309 DOI: 10.1128/mcb.25.9.3682-3689.2005] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Chromatin insulators, or boundary elements, appear to control eukaryotic gene expression by regulating interactions between enhancers and promoters. Boundaries have been identified in the 3' cis-regulatory region of Abd-B, which is subdivided into a series of separate iab domains. Boundary elements such as Mcp, Fab-7, and Fab-8 and adjacent silencers flank the iab domains and restrict the activity of the iab enhancers. We have identified an insulator in the 755-bp Mcp fragment that is linked to the previously characterized Polycomb response element (PRE) and silences the adjacent genes. This insulator blocks the enhancers of the yellow and white genes and protects them from PRE-mediated repression. The interaction between the Mcp elements, each containing the insulator and PRE, allows the eye enhancer to activate the white promoter over the repressed yellow domain. The same level of white activation was observed when the Mcp element combined with the insulator alone was interposed between the eye enhancer and the promoter, suggesting that the insulator is responsible for the interaction between the Mcp elements.
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Affiliation(s)
- Natalia Gruzdeva
- Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., 119334 Moscow, Russia
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