The DNA replication protein Orc1 from the yeast Torulaspora delbrueckii is required for heterochromatin formation but not as a silencer-binding protein.

ABSTRACT: To understand the process by which new protein functions emerge, we examined how the yeast heterochromatin protein Sir3 arose through gene duplication from the conserved DNA replication protein Orc1. Orc1 is a subunit of the origin recognition complex (ORC), which marks origins of DNA replication. In Saccharomyces cerevisiae, Orc1 also promotes heterochromatin assembly by recruiting the structural proteins Sir1-4 to silencer DNA. In contrast, the paralog of Orc1, Sir3, is a nucleosome-binding protein that spreads across heterochromatic loci in conjunction with other Sir proteins. We previously found that a nonduplicated Orc1 from the yeast Kluyveromyces lactis behaved like ScSir3 but did not have a silencer-binding function like ScOrc1. Moreover, K. lactis lacks Sir1, the protein that inte

SUBMITTER: Maria H 

PROVIDER: S-EPMC9434157 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature