title: Ty1 sequence with enhancer and mating-type-dependent regulatory activities.
abstract: Some insertion mutations in Saccharomyces cerevisiae activate the expression of adjacent structural genes. The CYC7-H2 mutation is a Ty1 insertion 5' to the iso-2-cytochrome c coding region of CYC7. The Ty1 insertion causes a 20-fold increase in CYC7 expression in a and alpha haploid cell types of S. cerevisiae. This activation is repressed in the a/alpha diploid cell type. Previous computer analysis of the CYC7-H2 Ty1 activator region identified two related sequences with homology both to mammalian enhancers and to a yeast a/alpha control site. A 112-base-pair (bp) DNA fragment encompassing one of these blocks of homology functioned as one component of the Ty1 activator. A 28-bp synthetic oligonucleotide with the wild-type homology block sequence was also functional. A single base pair mutation within the enhancer core of the synthetic 28-bp regulatory element reduced its activation ability to near background amounts. In addition, the 112-bp Ty1 fragment by itself functioned as a target for repression of adjacent gene expression in a/alpha diploid cells.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003574:Cytochrome c Group / Q000235:genetics; D045304:Cytochromes c; D004251:DNA Transposable Elements; D004171:Diploidy; D004742:Enhancer Elements, Genetic; D005796:Genes; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D005809:Genes, Regulator; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D003574:Cytochrome c Group; D004251:DNA Transposable Elements; C032139:iso-2-cytochrome C; D045304:Cytochromes c