Two new insulator proteins, Pita and ZIPIC, target CP190 to chromatin
- Oksana Maksimenko1,5,
- Marek Bartkuhn2,5,
- Viacheslav Stakhov1,5,
- Martin Herold2,5,
- Nickolay Zolotarev1,
- Theresa Jox2,
- Melanie K. Buxa2,
- Ramona Kirsch2,
- Artem Bonchuk3,
- Anna Fedotova1,
- Olga Kyrchanova3,
- Rainer Renkawitz2 and
- Pavel Georgiev4
- 1Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia;
- 2Institute for Genetics, Justus-Liebig-University Giessen, Heinrich-Buff-Ring, D-35392 Giessen, Germany;
- 3Group of Transcriptional Regulation, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia;
- 4Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Corresponding authors: georgiev_p{at}mail.ru, Rainer.Renkawitz{at}gen.bio.uni-giessen.de, olgina73{at}yandex.ru
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↵5 These authors contributed equally to this work.
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.
Footnotes
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[Supplemental material is available for this article.]
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Article published online before print. Article, supplemental material, and publication date are at http://www.genome.org/cgi/doi/10.1101/gr.174169.114.
Freely available online through the Genome Research Open Access option.
- Received February 19, 2014.
- Accepted October 14, 2014.
This article, published in Genome Research, is available under a Creative Commons License (Attribution 4.0 International), as described at http://creativecommons.org/licenses/by/4.0.
