Physical interaction between MSL2 and CLAMP assures direct cooperativity and prevents competition at composite binding sites.

ABSTRACT: MSL2, the DNA-binding subunit of the Drosophila dosage compensation complex, cooperates with the ubiquitous protein CLAMP to bind MSL recognition elements (MREs) on the X chromosome. We explore the nature of the cooperative binding to these GA-rich, composite sequence elements in reconstituted naïve embryonic chromatin. We found that the cooperativity requires physical interaction between both proteins. Remarkably, disruption of this interaction does not lead to indirect, nucleosome-mediated cooperativity as expected, but to competition. The protein interaction apparently not only increases the affinity for composite binding sites, but also locks both proteins in a defined dimeric state that prevents competition. High Affinity Sites of MSL2 on the X chromosome contain variable numbers of M

SUBMITTER: Eggers N 

PROVIDER: S-EPMC10516644 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature