Regulated nuclear localisation of the yeast transcription factor Ace2p controls expression of chitinase (CTS1) in Saccharomyces cerevisiae

Citation
C. O'Conallain et al., Regulated nuclear localisation of the yeast transcription factor Ace2p controls expression of chitinase (CTS1) in Saccharomyces cerevisiae, MOL G GENET, 262(2), 1999, pp. 275-282
Citations number
44
Categorie Soggetti
Molecular Biology & Genetics
Journal title
MOLECULAR AND GENERAL GENETICS
ISSN journal
00268925 → ACNP
Volume
262
Issue
2
Year of publication
1999
Pages
275 - 282
Database
ISI
SICI code
0026-8925(199909)262:2<275:RNLOTY>2.0.ZU;2-I
Abstract
The yeast transcription factor Ace2p regulates expression of the chitinase gene CTS1 in a cell cycle-dependent manner. Nuclear localisation of Ace2p i s restricted to late M and early G1 phases of the mitotic cell cycle. We sh ow here that this nuclear localisation is directly associated with regulati on of CTS1 expression. Using a version of Ace2p tagged with a c-myc epitope , we show that the protein is excluded from the nucleus of cells during mos t phases of the mitotic cell cycle. A mutant derivative in which one threon ine and two serine residues, which are candidate phosphorylation sites, wer e replaced by alanine (to mimic constitutive dephosphorylation) is localise d in the nucleus throughout the cell cycle. The mechanism of localisation o f Ace2p therefore involves regulation of its phosphorylation state, and clo sely resembles that used by the homologous transcription factor Swi5p. The wild-type Ace2 protein associates with Cdc28p in vivo, suggesting this may be the kinase that mediates the phosphorylation event. The stability of the protein is greatly reduced in a mutant that is constitutively localised to the nucleus, but is restored in a deletion derivative which remains in the cytoplasm. Ace2p is therefore controlled throughout the cell cycle at thre e levels: transcription, nuclear localisation, and proteolysis.