title: DRS1 to DRS7, novel genes required for ribosome assembly and function in Saccharomyces cerevisiae.
abstract: To identify Saccharomyces cerevisiae mutants defective in assembly or function of ribosomes, a collection of cold-sensitive strains generated by treatment with ethyl methanesulfonate was screened by sucrose gradient analysis for altered ratios of free 40S to 60S ribosomal subunits or qualitative changes in polyribosome profiles. Mutations defining seven complementation groups deficient in ribosomal subunits, drs1 to drs7, were identified. We have previously shown that DRS1 encodes a putative ATP-dependent RNA helicase necessary for assembly of 60S ribosomal subunits (T. L. Ripmaster, G. P. Vaughn, and J. L. Woolford, Jr., Proc. Natl. Acad. Sci. USA 89:11131-11135, 1992). Strains bearing the drs2 mutation process the 20S precursor of the mature 18S rRNA slowly and are deficient in 40S ribosomal subunits. Cloning and sequencing of the DRS2 gene revealed that it encodes a protein similar to membrane-spanning Ca2+ ATPases. The predicted amino acid sequence encoded by DRS2 contains seven transmembrane domains, a phosphate-binding loop found in ATP- or GTP-binding proteins, and a seven-amino-acid sequence detected in all classes of P-type ATPases. The cold-sensitive phenotype of drs2 is suppressed by extra copies of the TEF3 gene, which encodes a yeast homolog of eukaryotic translation elongation factor EF-1 gamma. Identification of gene products affecting ribosome assembly and function among the DNAs complementing the drs mutations validates the feasibility of this approach.
authors.affiliation: Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213.
authors.forename: T L
authors.initials: TL
authors.lastname: Ripmaster
authors.forename: G P
authors.initials: GP
authors.lastname: Vaughn
authors.forename: J L
authors.initials: JL
authors.lastname: Woolford
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D000252:Calcium-Transporting ATPases; D002874:Chromosome Mapping; D004271:DNA, Fungal / Q000235:genetics; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000235:genetics; D012322:RNA Precursors / Q000378:metabolism; D012331:RNA, Fungal / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D015183:Restriction Mapping; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: D004271:DNA, Fungal; C104014:DRS2 protein, S cerevisiae; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D012322:RNA Precursors; D012331:RNA, Fungal; D012337:RNA, Ribosomal, 18S; D029701:Saccharomyces cerevisiae Proteins; D000251:Adenosine Triphosphatases; D000252:Calcium-Transporting ATPases