From Gene Repression to the Maintenance of Facultative Heterochromatin: A Molecular Basis

Repressive histone methyltransferases maintain genes in a repressed state and are required for the normal development of metazoan species. Previous evidence suggested that repressive transcription factors bind to repressive histone methyltransferases to recruit them to chromatin, but such interactions could not be detected here. Instead, physical interactions were mapped between other chromatin-associated factors and histone methyltransferases using various biophysical approaches. Additionally, using reconstituted systems and in vitro enzymatic assays, this thesis highlights how regulatory factors affect the chromatin-modification activity of repressive histone methyltransferase. Overall, this thesis provides insights into multifactorial mechanisms responsible for maintaining the repressed state of genes.