Identification of a Saccharomyces cerevisiae mitochondrial-DNA which can act as a promoter tightly regulated by carbon source when placed in the nucleus.
Screening of a promoter probe gene bank for DNA sequences that could act as inducible promoters following growth on non-fermentable carbon sources led to the identification of the mitochondrially encoded cytochrome oxidase subunit 1 gene (COX1) as an active sequence. Carbon-source regulation of this promoter was confirmed by a beta-galactosidase assay which showed a 31- and 180-fold induction of expression after growth on ethanol or lactate-based media respectively. Two elements matching the CCAAT-binding-factor motif, which is involved in activating transcription on non-fermentable carbon sources, were identified in the putative promoter. Expression was found to be reduced to low levels in otherwise isogenic hap3 and hap4 mutant strains. Thus, this mitochondrial DNA when placed in the nucleus can act as a promoter that is subject to strict carbon-source regulation. These observations are discussed both with respect to the origin of the S. cerevisiae COX1 gene in particular and with respect to the origin of introns in general.
MacIver
F H
FH
C.R.C for Food Industry Innovation, School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, NSW 2052, Australia.
Dawes
I W
IW
Grant
C M
CM
D015139:Blotting, Southern; D023081:CCAAT-Binding Factor; D002244:Carbon / Q000494:pharmacology; D002467:Cell Nucleus / Q000235:genetics*; D003001:Cloning, Molecular; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics; D000431:Ethanol / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D014644:Genetic Variation; D007438:Introns; D007763:Lac Operon; D019344:Lactic Acid / Q000378:metabolism; D016366:Open Reading Frames; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
D023081:CCAAT-Binding Factor; D004272:DNA, Mitochondrial; D005656:Fungal Proteins; C490431:HAP3 protein, S cerevisiae; C061437:HAP4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D019344:Lactic Acid; D000431:Ethanol; D002244:Carbon; D003576:Electron Transport Complex IV; D001616:beta-Galactosidase