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Kluyveromyces lactis SSO1 and SEB1 genes are functional in Saccharomyces cerevisiae and enhance production of secreted proteins when overexpressed
Author(s) -
Toikkanen Jaana H.,
Sundqvist Lena,
Keränen Sirkka
Publication year - 2004
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1151
Subject(s) - kluyveromyces lactis , biology , saccharomyces cerevisiae , kluyveromyces , yeast , gene , homology (biology) , secretion , secretory protein , mutant , pichia pastoris , secretory pathway , biochemistry , recombinant dna , golgi apparatus , cell
The SEB1 / SBH1 and the SSO genes encode components of the protein secretory machinery functioning at the opposite ends, ER translocation and exocytosis, respectively, of the secretory pathway in Saccharomyces cerevisiae . Overexpression of these genes can rescue temperature‐sensitive ( ts ) growth defect of many sec mutants impaired in protein secretion. Furthermore, their overexpression in wild‐type yeast enhances production of secreted proteins in S. cerevisiae , which suggests that they may be rate‐limiting factors in this process. Here we report isolation of Kluyveromyces lactis homologues of these genes. KlSSO1 and KlSEB1 were isolated as clones capable of rescuing growth of ts sso2‐1 and seb1Δ seb2Δ sem1Δ strains, respectively, at the restrictive temperature. The encoded Kluyveromyces proteins are up to 70% identical with the S. cerevisiae homologues at the amino acid level and can functionally replace them. Interestingly, KlSSO1 and KlSEB1 show similar enhancing effect on production of a secreted protein as the SSO and SEB1 genes of S. cerevisiae when overexpressed. In accordance with the high homology level of the secretory pathway proteins in different yeast species, the polyclonal antibodies raised against S. cerevisiae Seb1p, Sso2p and Sec4p can detect homologous proteins in cell lysates of K. lactis and Pichia pastoris , the latter also in Candida utilis. The GenBank Accession Nos are AF307983 ( K. lactis SSO1 ) and AF318314 ( K. lactis SEB1 ). Copyright © 2004 John Wiley & Sons, Ltd.