title: Yeast gene SRP1 (serine-rich protein). Intragenic repeat structure and identification of a family of SRP1-related DNA sequences.
abstract: We have isolated and sequenced a yeast gene encoding a protein (Mr 24,875) very rich in serine (SRP) and alanine residues that accounted for 25% and 20% of the total amino acids, respectively. The SRP1 gene is highly expressed in culture conditions leading to glucose repression (Marguet & Lauquin, 1986), the amount of SRP1 mRNA representing about 1 to 2% of total poly(A)+ RNA. A repetitive structure of eight direct tandem repeats 36-base long, also reflected in the amino acid sequence, was found in the second half of the open reading frame. The consensus amino acid sequence of the repeat was Ser-Ser-Ser-Ala-Ala-Pro-Ser-Ser-Ser-Glu-Ala-Lys. Replacing the genomic copy of the cloned gene with a disrupted SRP1 gene indicated that the SRP1 gene was not essential for viability in yeast, but several SRP1-homologous sequences were found within the yeast genome, raising the possibility that the disrupted SRP1 gene is rescued by one of the other SRP-homologous sequences. Complete separation of yeast chromosomes by contour-clamped homogeneous field electrophoresis indicated that, apart from chromosome V, which carries the SRP1 gene, 12 chromosomes have SRP-related sequences with various degrees of homology. These sequences were located on chromosomes XV, VII and XI under stringent conditions of hybridization (tm -20 degrees C), and observed on chromosomes I, II, III, IV, VI, VIII, X, XI and XII, only under low-stringency conditions (tm -40 degrees C). Northern blot analysis of both the wild type and SRP1-disrupted strains indicated that along with SRP1 at least one more member of the SRP family was transcribed to a 0.7 kb (1 kb = 10(3) bases) polyadenylated RNA species clearly distinct from the SRP1-specific mRNA (1 kb long). Analyses of the SRP1 repeat domain suggested a model for the divergent evolution of the repeats in the SRP1 sequence.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D006360:Heat-Shock Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D011110:Polymorphism, Genetic; D012331:RNA, Fungal; D012333:RNA, Messenger; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012694:Serine; D014158:Transcription, Genetic
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C491115:TIR1 protein, S cerevisiae; D012694:Serine