Normal telomere length maintenance in Saccharomyces cerevisiae requires nuclear import of the ever shorter telomeres 1 (Est1) protein via the importin alpha pathway.

ABSTRACT: The Est1 (ever shorter telomeres 1) protein is an essential component of yeast telomerase, a ribonucleoprotein complex that restores the repetitive sequences at chromosome ends (telomeres) that would otherwise be lost during DNA replication. Previous work has shown that the telomerase RNA component (TLC1) transits through the cytoplasm during telomerase biogenesis, but mechanisms of protein import have not been addressed. Here we identify three nuclear localization sequences (NLSs) in Est1p. Mutation of the most N-terminal NLS in the context of full-length Est1p reduces Est1p nuclear localization and causes telomere shortening-phenotypes that are rescued by fusion with the NLS from the simian virus 40 (SV40) large-T antigen. In contrast to that of the TLC1 RNA, Est1p nuclear import is faci

SUBMITTER: Hawkins C 

PROVIDER: S-EPMC4135794 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature