The S. cerevisiae SEC65 gene encodes a component of yeast signal recognition particle with homology to human SRP19

TRANSLOCATION of proteins across the endoplasmic reticulum (ER) membrane represents the first step in the eukaryotic secretory pathway. In mammalian cells, the targeting of secretory and membrane protein precursors to the ER is mediated by signal recognition particle (SRP), a cytosolic ribonucleoprotein complex comprising a molecule of 7SL RNA and six polypeptide subunits (relative molecular masses 9, 14, 19, 54, 68 and 72K)1. In Sac-charomyces cerevisiae, a homologue of the 54K subunit (SRP54)2,3co-purifies with a small cytoplasmic RNA, scRl (refs 4, 5). Genetic data indicate that SRP54 and scRl are involved in translocation in vivo, suggesting the existence of an SRP-like activity in yeast5,6. Whether this activity requires additional components similar to those found in mammalian SRP is not known. We have recently reported a genetic selection that led to the isolation of a yeast mutant, sec65-l, which is conditionally defective in the insertion of integral membrane proteins into the ER7. Here we report the cloning and sequencing of the SEC65 gene, which encodes a 31.2K protein with significant sequence similarity to the 19K subunit of human SRP (SRP19)8. We also report the cloning of a multicopy suppressor of sec65-l, and its identification as the previously definedSRP54gene, providing genetic evidence for an interaction between these gene products in vivo

[1]  M. Uhlén,et al.  Immobilization and purification of enzymes with staphylococcal protein A gene fusion vectors. , 1985, The EMBO journal.

[2]  B. Hann,et al.  SEC65 gene product is a subunit of the yeast signal recognition particle required for its integrity , 1992, Nature.

[3]  A. Nakano,et al.  SRH1 protein, the yeast homologue of the 54 kDa subunit of signal recognition particle, is involved in ER translocation of secretory proteins , 1991, FEBS letters.

[4]  S. Henikoff.  Unidirectional digestion with exonuclease III in DNA sequence analysis. , 1987, Methods in enzymology.

[5]  A. Myers,et al.  Yeast/E. coli shuttle vectors with multiple unique restriction sites , 1986, Yeast.

[6]  K. Struhl.  Nucleotide sequence and transcriptional mapping of the yeast pet56-his3-ded1 gene region. , 1985, Nucleic acids research.

[7]  K. Gull,et al.  Definition of individual components within the cytoskeleton of Trypanosoma brucei by a library of monoclonal antibodies. , 1989, Journal of cell science.

[8]  R. Sikorski,et al.  A system of shuttle vectors and yeast host strains designed for efficient manipulation of DNA in Saccharomyces cerevisiae. , 1989, Genetics.

[9]  F. Felici,et al.  The most abundant small cytoplasmic RNA of Saccharomyces cerevisiae has an important function required for normal cell growth , 1989, Molecular and cellular biology.

[10]  C. Zwieb,et al.  Isolation and characterization of a cDNA clone encoding the 19 kDa protein of signal recognition particle (SRP): expression and binding to 7SL RNA. , 1988, Nucleic acids research.

[11]  Isolation of a yeast gene, SRH1, that encodes a homologue of the 54K subunit of mammalian signal recognition particle. , 1990, Journal of biochemistry.

[12]  Peter Walter,et al.  Signal recognition particle contains a 7S RNA essential for protein translocation across the endoplasmic reticulum , 1982, Nature.

[13]  J. Vieira,et al.  Production of single-stranded plasmid DNA. , 1987, Methods in enzymology.

[14]  B. Hann,et al.  The signal recognition particle in S. cerevisiae , 1991, Cell.

[15]  J W Szostak,et al.  Yeast transformation: a model system for the study of recombination. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[16]  B. Hann,et al.  Saccharomyces cerevisiae and Schizosaccharomyces pombe contain a homologue to the 54-kD subunit of the signal recognition particle that in S. cerevisiae is essential for growth , 1989, The Journal of cell biology.

[17]  R. Schekman,et al.  Structural and functional dissection of Sec62p, a membrane-bound component of the yeast endoplasmic reticulum protein import machinery , 1990, Molecular and cellular biology.

[18]  C. Guthrie,et al.  Genetic analysis of small nuclear RNAs in Saccharomyces cerevisiae: viable sextuple mutant , 1988, Molecular and cellular biology.