Mutations in Pdd1 reveal distinct requirements for its chromodomain and chromoshadow domain in directing histone methylation and heterochromatin elimination.

ABSTRACT: Pdd1, a specialized HP1-like protein, is required for genome-wide DNA rearrangements that restructure a previously silent germ line genome into an active somatic genome during macronuclear differentiation of Tetrahymena thermophila. We deleted or otherwise mutated conserved regions of the protein to investigate how its different domains promote the excision of thousands of internal eliminated sequences (IESs). Previous studies revealed that Pdd1 contributes to recognition of IES loci after they are targeted by small-RNA-guided methylation of histone H3 on lysine 27 (H3K27), subsequently aids the establishment of H3K9 methylation, and recruits proteins that lead to excision. The phenotypes we observed for different Pdd1 alleles showed that each of the two chromodomains and the chromoshadow

SUBMITTER: Schwope RM 

PROVIDER: S-EPMC3910979 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature