Functional role of the c-terminal domains of the msl2 protein of drosophila melanogaster

Dosage compensation complex, consisting of five proteins and two non-coding RNAs roX, specifically binds to the X chromosome in males, providing a higher level of gene expression, which is necessary to compensate for the monosomy of the sex chromosome in male Drosophila compared to two X chromosomes in females. The MSL2 protein contains an N-terminal RING domain, which acts as an E3 ligase in the ubiquitination of proteins and is the only subunit of the complex that is expressed only in males. The functional role of two C-terminal domains of the MSL2 protein, enriched with proline (P-domain) and basic amino acids (B-domain), was investigated. As a result, it was shown that the B-domain destabilizes the MSL2 protein, which is associated with the presence of two lysines whose ubiquitination is under the control of the RING domain of MSL2. The unstructured proline-rich domain stimulates transcription of the roX2 gene, which is necessary for the effective formation of the dosage compensation complex.