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Ibf1 and I bf2 are novel CP 190‐interacting proteins required for insulator function
Author(s) -
Cuartero Sergi,
Fresán Ujué,
Reina Oscar,
Planet Evarist,
Espinàs M Lluisa
Publication year - 2014
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/embj.201386001
Subject(s) - chromatin , biology , dna binding protein , microbiology and biotechnology , plasma protein binding , regulation of gene expression , enhancer , ctcf , genetics , transcription factor , gene
Insulators are DNA ‐protein complexes that play a central role in chromatin organization and regulation of gene expression. In D rosophila different proteins, d CTCF , S u( H w), and BEAF bind to specific subsets of insulators most of them having in common CP 190. It has been shown that there are a number of CP 190‐binding sites that are not shared with any other known insulator protein, suggesting that other proteins could cooperate with CP 190 to regulate insulator activity. Here we report on the identification of two previously uncharacterized proteins as CP 190‐interacting proteins, that we have named I bf1 and I bf2. These proteins localize at insulator bodies and associate with chromatin at CP 190‐binding sites throughout the genome. We also show that I bf1 and I bf2 are DNA ‐binding proteins that form hetero‐oligomers that mediate CP 190 binding to chromatin. Moreover, I bf1 and I bf2 are necessary for insulator activity in enhancer‐blocking assays and I bf2 null mutation cause a homeotic phenotype. Taken together our data reveal a novel pathway of CP 190 recruitment to chromatin that is required for insulator activity.