Open AccessThesal3+ Gene Encodes an Importin-β Implicated in the Nuclear Import of Cdc25 inSchizosaccharomyces pombe
Author(s) -
Gordon Chua,
Carol Lingner,
Corey Frazer,
Paul G. Young
Publication year - 2002
Publication title -
genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.792
H-Index - 246
eISSN - 1943-2631
pISSN - 0016-6731
DOI - 10.1093/genetics/162.2.689
Subject(s) - biology , importin , schizosaccharomyces pombe , cdc25 , mitosis , nuclear transport , microbiology and biotechnology , mutant , schizosaccharomyces , nuclear localization sequence , nuclear pore , nuclear protein , gene , cell nucleus , genetics , cell cycle , nucleus , cyclin dependent kinase 1 , transcription factor
In Schizosaccharomyces pombe, the nuclear accumulation of Cdc25 peaks in G2 and is necessary for the proper timing of mitotic entry. Here, we identify the sal3(+) gene product as an importin-beta homolog that participates in the nuclear import of Cdc25. Loss of sal3(+) results in a cell cycle delay, failure to undergo G1 arrest under nitrogen-starvation conditions, and mislocalization of Cdc25 to the cytosol. Fusion of an exogenous classical nuclear localization sequence (cNLS) to Cdc25 restores its nuclear accumulation in a sal3 disruptant and suppresses the sal3 mutant phenotypes. In addition, we show that enhanced nuclear localization of Cdc25 at endogenous levels of expression advances the onset of mitosis. These results demonstrate that the nuclear translocation of Cdc25 is important for the timing of mitotic entry and that Sal3 plays an important role in this process.