The heterochromatin protein Swi6/HP1 activates replication origins at the pericentromeric region and silent mating-type locus.

摘要: Heterochromatin is a structurally compacted region of chromosomes in which transcription and recombination are inactivated. DNA replication temporally regulated heterochromatin, but the molecular mechanism for regulation has not been elucidated. Among heterochromatin loci Schizosaccharomyces pombe, pericentromeric silent mating-type (mat) locus replicate early S phase, whereas sub-telomeric does not, suggesting complex mechanisms heterochromatic regions. Here, we show that Swi6, an S. pombe counterpart protein 1 (HP1), required mat locus. Origin-loading Sld3, depends on Dfp1/Dbf4-dependent kinase Cdc7 (DDK), stimulated by Swi6. An HP1-binding motif within Dfp1 interaction with Swi6 vitro Tethering to swi6-deficient cells restores these loci. Our results positively regulates initiation silenced chromatin interacting essential kinase.