Isolation and characterization of SGE1: a yeast gene that partially suppresses the gal11 mutation in multiple copies
1993
Amakasu, H. | Suzuki, Y. | Nishizawa, M. | Fukasawa, T.
Recessive mutations of GAL11 in Saccharomyces cerevisiae cause pleiotropic defects that include weak fermentation of galactose, alpha-specific sterility and slow growth on nonfermentable carbon sources. Recent experiments suggest that Gal1 1p functions as a "coactivator" that links transcriptional activators, such as Ga14p and Grf1p/Rap1p/Tuf1p, with the basic transcription machinery. In the present experiments we isolated a gene, SGE1, that suppresses gal11 for growth on ethidium bromide/ galactose agar when the gene was present in two or more copies. The other gal11 phenotypes were not suppressed by SGE1 in the multiple-copy state. Multiple copies of SGE1 increased expression of galactose-inducible genes in gal11 yeast, presumably at the level of transcription. When SGE1 was disrupted in wild-type yeast, the expression of galactose-inducible genes decreased to 50-60% of the wild-type level, presumably due to effect on transcription. Complete DNA sequence analysis revealed that SGE1 encodes a predicted protein of 543 amino acids. SGE1-specific mRNA of 1.8 kilonucleotides was detected by Northern analysis along the direction of the open reading frame. The gene mapped near RAD56 at the right end of chromosome 16.
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