The Chromatin Remodeler, Mit1, Enables the Propagation of the Histone Modification, H3K9me

ATP-dependent chromatin remodelers are key effectors in this process, modulating nucleosome positioning to establish either open or repressive chromatin states. The CHD family of remodelers exhibits diverse roles in transcriptional regulation, yet the mechanisms by which they contribute to transcriptional silencing remain incompletely understood.

In Schizosaccharomyces pombe, the CHD remodeler Mit1 functions within the SHREC complex to enforce heterochromatin formation, but its precise mode of action is unclear. Here, we directly tether Mit1 to an ectopic chromatin locus and demonstrate that Mit1 recruitment induces transcriptional gene silencing and nucleates broad domains of H3K9 methylation in a manner dependent on the Clr4 methyltransferase. This silencing requires Mit1’s remodeling activity but does not involve direct physical interaction with Clr4, indicating that Mit1 remodels chromatin to create a substrate favorable for Clr4 function.