Two new insulator proteins, Pita and ZIPIC, target CP190 to chromatin
- Oksana Maksimenko1,
- Marek Bartkuhn2,
- Viacheslav Stakhov1,
- Martin Herold2,
- Nickolay Zolotarev1,
- Theresa Jox2,
- Melanie K Buxa2,
- Ramona Kirsch2,
- Artem Bonchuk1,
- Anna Fedotova1,
- Olga Kyrchanova1,
- Rainer Renkawitz2,3 and
- Pavel Georgiev1
- ↵* Corresponding author; email: rainer.renkawitz{at}gen.bio.uni-giessen.de
Abstract
Insulators are multi-protein - 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.
- Received February 19, 2014.
- Accepted October 14, 2014.
- Published by Cold Spring Harbor Laboratory Press
This manuscript is Open Access.
This article, published in Genome Research, is available under a Creative Commons License (Attribution 4.0 International license), as described at http://creativecommons.org/licenses/by/4.0/.
