biostudies-literatureZhong ZNIGMS NIH HHS96https://www.ebi.ac.uk/biostudies/studies/S-EPMC10131428biostudies-literatureUnknown24(1)<h4>Background</h4>The microrchidia (MORC) proteins are a family of evolutionarily conserved GHKL-type ATPases involved in chromatin compaction and gene silencing. Arabidopsis MORC proteins act in the RNA-directed DNA methylation (RdDM) pathway, where they act as molecular tethers to ensure the efficient establishment of RdDM and de novo gene silencing. However, MORC proteins also have RdDM-independent functions although their underlying mechanisms are unknown.<h4>Results</h4>In this study, we examine MORC binding regions where RdDM does not occur in order to shed light on the RdDM-independent functions of MORC proteins. We find that MORC proteins compact chromatin and reduce DNA accessibility to transcription factors, thereby repressing gene expression. We also find that MORC-mediated repGenome biologyMORC proteins regulate transcription factor binding by mediating chromatin compaction in active chromatin regions.PMC10131428R35 GM130272Wang MKe YLi ZLiu MHarris CJJami-Alahmadi YZhong ZFeng SWohlschlegel JAXue YZhou JJacobsen SEfalseMORC proteins regulate transcription factor binding by mediating chromatin compaction in active chromatin regions.<h4>Background</h4>The microrchidia (MORC) proteins are a family of evolutionarily conserved GHKL-type ATPases involved in chromatin compaction and gene silencing. Arabidopsis MORC proteins act in the RNA-directed DNA methylation (RdDM) pathway, where they act as molecular tethers to ensure the efficient establishment of RdDM and de novo gene silencing. However, MORC proteins also have RdDM-independent functions although their underlying mechanisms are unknown.<h4>Results</h4>In this study, we examine MORC binding regions where RdDM does not occur in order to shed light on the RdDM-independent functions of MORC proteins. We find that MORC proteins compact chromatin and reduce DNA accessibility to transcription factors, thereby repressing gene expression. We also find that MORC-mediated rep2023-01-01T00:00:00Z2023 Apr2025-04-22T13:10:25.258Z2025-04-06T00:33:44.594ZS-EPMC101314283710121810.1186/s13059-023-02939-4