title: Selective interactions of boundaries with upstream region of Abd-B promoter in Drosophila bithorax complex and role of dCTCF in this process.
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.
authors.affiliation: Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St, Moscow 119334, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Kyrchanova
authors.forename: Tatiana
authors.initials: T
authors.lastname: Ivlieva
authors.forename: Stepan
authors.initials: S
authors.lastname: Toshchakov
authors.forename: Alexander
authors.initials: A
authors.lastname: Parshikov
authors.forename: Oksana
authors.initials: O
authors.lastname: Maksimenko
authors.forename: Pavel
authors.initials: P
authors.lastname: Georgiev
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001665:Binding Sites; D000076246:CCCTC-Binding Factor; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics*; D038101:Insulator Elements; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: C062393:Abd-B proteins, Drosophila; D000076246:CCCTC-Binding Factor; C524946:CTCF protein, Drosophila; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C052130:GAL4 protein, S cerevisiae; D018398:Homeodomain Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors