The role of roX RNA for structure and function of the dosage compensation complex.

• Applicant: Professor Dr. Peter Burkhard Becker
• Subject Area: General Genetics and Functional Genome Biology ; Biochemistry
• Term: from 2018 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 417339159

Complex eukaryotic genomes encode abundant long, non-coding (lnc) RNAs. Our knowledge of the molecular mechanisms underlying chromatin-based lncRNA function is scarce.We will study a paradigmatic, multi-enzyme chromatin regulator, which absolutely requires lncRNA for assembly and function. The dosage compensation complex (DCC) of Drosophila melanogaster consists of five male-specific-lethal (MSL) proteins that assemble with non-coding roX RNA to form a regulatory complex with special properties: the DCC doubles the transcription of most genes on the single X chromosome in male cells to match the combined output of the two Xs in females.Although the protein subunits alone can associate with each other and are active enzymes in vitro, the association of roX is a vital requirement for DCC function in cells. RoX function, however, is mysterious. Secondary structure remodeling of roX by the DExH helicase MLE initiates association of MSL proteins towards assembly of a functional DCC. We hypothesize that the MSL proteins acquire their dedicated functionality within the DCC by association with roX. We aim to elucidate the molecular basis of lncRNA roX integration into the DCC to understand the roX dependency of DCC assembly and activity. To this end, we will study the mechanisms of roX incorporation in detail, optimise the assembly of DCC containing specific RNA and characterize the roX-MSL interactions through specific protein-RNA interaction assays (involving crosslinking, sequencing and mass spectrometry). Our final goal is to compare MSL assemblies in the presence and absence of specific RNA and to correlate structural changes with refined MSL functions.Our study will shed light on a fascinating, highly evolved chromatin regulator. More importantly, we strive to uncover regulatory principles of lncRNA function of general relevance and broad applicability for the emerging field of lncRNA biology.

• DFG Programme: Research Grants