Open AccessIdentification and characterization of a gene required for α1,2‐mannose extension in the O ‐linked glycan synthesis pathway in Schizosaccharomyces pombe
Author(s) -
Ikeda Yuka,
Ohashi Takao,
Tanaka Naotaka,
Takegawa Kaoru
Publication year - 2009
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2008.00458.x
Subject(s) - schizosaccharomyces pombe , biology , glycan , mannose , identification (biology) , schizosaccharomyces , gene , computational biology , biochemistry , botany , saccharomyces cerevisiae , glycoprotein
The KTR α1,2‐mannosyltransferase gene family of Saccharomyces cerevisiae is responsible not only for outer‐chain modifications of N ‐linked oligosaccharides but also for elongation of O ‐linked mannose residues. To identify genes involved in the elongation step of O ‐linked oligosaccharide chains in Schizosaccharomyces pombe , we characterized six genes, omh1 + –omh6 + , that share significant sequence similarity to the S. cerevisiae KTR family. Six deletion strains were constructed, each carrying a single disrupted omh allele. All strains were viable, indicating that none of the omh genes was essential. Heterologous expression of a chitinase from S. cerevisiae in the omh mutants revealed that O ‐glycosylation of chitinase had decreased in omh1 Δ cells, but not in the other mutants, indicating that the other omh genes do not appear to be required for O ‐glycan synthesis. Addition of the second α1,2‐linked mannose residue was blocked in omh1 Δ cells. An Omh1–GFP fusion protein was found to be localized in the Golgi apparatus. These results indicate that Omh1p plays a major role in extending α1,2‐linked mannose in the O ‐glycan pathway in S. pombe .