A 15-base-pair element activates the SPS4 gene midway through sporulation in Saccharomyces cerevisiae.
Sporulation of the yeast Saccharomyces cerevisiae represents a simple developmental process in which the events of meiosis and spore wall formation are accompanied by the sequential activation of temporally distinct classes of genes. In this study, we have examined expression of the SPS4 gene, which belongs to a group of genes that is activated midway through sporulation. We mapped the upstream boundary of the regulatory region of SPS4 by monitoring the effect of sequential deletions of 5'-flanking sequence on expression of plasmid-borne versions of SPS4 introduced into a MATa/MAT alpha delta sps4/delta sps4 strain. This analysis indicated that the 5' boundary of the regulatory region was within 50 bp of the putative TATA box of the gene. By testing various oligonucleotides that spanned this boundary and the downstream sequence for their ability to activate expression of a heterologous promoter, we found that a 15-bp sequence sufficed to act as a sporulation-specific upstream activation sequence. This 15-bp fragment, designated UASSPS4, activated expression of a CYC1-lacZ reporter gene midway through sporulation and was equally active in both orientations. Extending the UAS fragment to include the adjacent 14-bp enhanced its activity 10-fold. We show that expression of SPS4 is regulated in a manner distinct from that of early meiotic genes: mutation of UME6 did not lead to vegetative expression of SPS4, and sporulation-specific expression was delayed by mutation of IME2. In vivo and in vitro assays suggested that a factor present in vegetative cells bind to the UASSPS4 element. We speculate that during sporulation this factor is modified to serve as an activator of the SPS4 gene or, alternatively, that it recruits an activator to the promoter.
Hepworth
S R
SR
Department of Biochemistry, University of Toronto, Ontario, Canada.
Ebisuzaki
L K
LK
Segall
J
J
D001483:Base Sequence; D018797:Cell Cycle Proteins; D004252:DNA Mutational Analysis; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D008540:Meiosis / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics; D017346:Protein Serine-Threonine Kinases; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D013172:Spores, Fungal / Q000235:genetics* / Q000254:growth & development; D014157:Transcription Factors / Q000235:genetics
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D003854:Deoxyribonucleotides; D005656:Fungal Proteins; C080326:IME1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; C542269:SPS4 protein, S cerevisiae; C051095:SSP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C089979:UME6 protein, S cerevisiae; D011494:Protein Kinases; C064979:IME2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases