Functional Role of C-terminal Domains in the MSL2 Protein of Drosophila melanogaster

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Evgeniya A. Tikhonova¹, Pavel G. Georgiev¹, and Oksana G. Maksimenko^1,a*

¹Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia

Received September 30, 2023; Revised December 11, 2023; Accepted December 12, 2023

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Dosage compensation complex (DCC), which consists of five proteins and two non-coding RNAs roX, specifically binds to the X chromosome in males, providing a higher level of gene expression necessary to compensate for the monosomy of the sex chromosome in male Drosophila compared to the two X chromosomes in females. The MSL2 protein contains the N-terminal RING domain, which acts as an E3 ligase in ubiquitination of proteins and is the only subunit of the complex expressed only in males. Functional role of the 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 ubiquitination of which is under control of the RING domain of MSL2. The unstructured proline-rich domain stimulates transcription of the roX2 gene, which is necessary for effective formation of the dosage compensation complex.

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KEY WORDS: dosage compensation, long non-coding RNAs, MSL1, roX, MSL complex, ubiquitination

DOI: 10.1134/S0006297924040060

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