Identification and characterization of a human MORC2 DNA binding region that is required for gene silencing

The eukaryotic microrchidia (MORC) protein family are DNA gyrase, Hsp90, histidine kinase, MutL (GHKL)-type ATPases involved in gene expression regulation and chromatin compaction. The molecular mechanisms underlying these activities are incompletely understood. Here, we studied the full-length human MORC2 protein biochemically. We identified a DNA binding site in the C-terminus of the protein, and we observe that this region can be phosphorylated in cells. DNA binding by MORC2 reduces its ATPase activity and MORC2 can entrap multiple DNA substrates between its N-terminal GHKL and C-terminal coiled coil 3 dimerization domains. Finally, we observe that the MORC2 C-terminal DNA binding region is required for gene silencing in cells. Together, our data provide a model to understand how MORC2 engages with DNA substrates to mediate gene silencing. Overall design: The eukaryotic microrchidia (MORC) protein family are DNA gyrase, Hsp90, histidine kinase, MutL (GHKL)-type ATPases involved in gene expression regulation and chromatin compaction. We identified a DNA binding site in the C-terminus of the protein. Here we generated dox-inducible GFP, GFP-MORC2, and GFP-MORC2 DNA-binding mutants and performed RNA-sequencing. We show that the MORC2 C-terminal DNA binding region is required for gene silencing in cells. Our data provide a model to understand how MORC2 engages with DNA substrates to mediate gene silencing. Here we generated dox-inducible GFP, GFP-MORC2, and GFP-MORC2 DNA-binding mutants and performed RNA-sequencing. Biological replicates were defined as replicate doxycycline inductions of GFP transgenes. N=3 biological replicates were performed for each overexpression