Tikhonova, E., Fedotova, A., Bonchuk, A., Mogila, V., Larschan, E.N., Georgiev, P., Maksimenko, O. (2019). The simultaneous interaction of MSL2 with CLAMP and DNA provides redundancy in the initiation of dosage compensation in Drosophila males.  Development 146(19): dev179663.

FBrf0243283

Research paper

The binding of the Drosophila male-specific lethal dosage compensation complex (DCC) exclusively to the male X chromosome provides an excellent model system to understand mechanisms of selective recruitment of protein complexes to chromatin. Previous studies showed that the male-specific organizer of the complex, MSL2, and the ubiquitous DNA-binding protein CLAMP are key players in the specificity of X chromosome binding. The CXC domain of MSL2 binds to genomic sites of DCC recruitment in vitro Another conserved domain of MSL2, named Clamp-binding domain (CBD) directly interacts with the N-terminal zinc-finger domain of CLAMP. Here, we found that inactivation of CBD or CXC individually only modestly affected recruitment of the DCC to the X chromosome in males. However, combination of these two genetic lesions within the same MSL2 mutant resulted in an increased loss of DCC recruitment to the X chromosome. Thus, proper MSL2 positioning requires an interaction with either CLAMP or DNA to initiate dosage compensation in Drosophila males.