title: Isolation of a Trichoderma reesei cDNA encoding GTP: a-D-mannose-1-phosphate guanyltransferase involved in early steps of protein glycosylation.
abstract: A cDNA coding for GTP: alpha-d-mannose-1-phosphate guanyltransferase (MPG1 transferase) (EC 2.7.7.13) was isolated from a cDNA library of the Trichoderma reesei RutC-30 strain by suppression of the yeast Saccharomyces cerevisiae mutation in the DPM1gene encoding mannosylphosphodolichol (MPD) synthase. The nucleotide sequence of the 1.6 kb-long cDNA revealed an ORF which encodes a protein of 364 amino acids. Sequence comparisons demonstrate 70% identity with the S. cerevisiae guanyl transferase gene (MPG1) and 75% identity with the Schizosaccharomyces pombe homologue. No similarity was found with the MPD synthase encoded by the S. cerevisiae DPM1 gene. The possibility that cloned cDNA encodes a product with a MPD synthase activity was also excluded by transforming a heterozygous S. cerevisiae dpm1::LEU2/DPM1 diploid, which did not lead to the restoration of viability of the dpm1 spores. Simultaneously, a significant increase in MPG transferase activity, as compared with the wild-type yeast, was observed in cellular extracts when the mpg1 cDNA from Trichoderma was expressed in the S. cerevisiae dpm1-6 mutant.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawin'skiego 5 a, 02 106 Warsaw, Poland.
authors.forename: J S
authors.initials: JS
authors.lastname: Kruszewska
authors.forename: M
authors.initials: M
authors.lastname: Saloheimo
authors.forename: M
authors.initials: M
authors.lastname: Penttilä
authors.forename: G
authors.initials: G
authors.lastname: Palamarczyk
mesh_terms: D000595:Amino Acid Sequence; D002999:Clone Cells / Q000502:physiology; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification*; D005656:Fungal Proteins / Q000378:metabolism*; D005816:Genetic Complementation Test; D006031:Glycosylation; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009713:Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics; D014242:Trichoderma / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D005656:Fungal Proteins; D014157:Transcription Factors; D009713:Nucleotidyltransferases; C026917:mannose 1-phosphate guanylyltransferase