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Identification by functional analysis of the gene encoding α‐isopropylmalate synthase II ( LEU9 ) in Saccharomyces cerevisiae
Author(s) -
Casalone Enrico,
Barberio Claudia,
Cavalieri Duccio,
Polsinelli Mario
Publication year - 2000
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/(sici)1097-0061(200004)16:6<539::aid-yea547>3.0.co;2-k
Subject(s) - biology , auxotrophy , open reading frame , mutant , gene , homology (biology) , saccharomyces cerevisiae , microbiology and biotechnology , genetics , plasmid , biochemistry , peptide sequence
The function of the open reading frame (ORF) YOR108w of Saccharomyces cerevisiae has been analysed. The deletion of this ORF from chromosome XV did not give an identifiable phenotype. A mutant in which both ORF YOR108w and LEU4 gene have been deleted proved to be leucine auxotrophic and α‐isopropylmalate synthase (α‐IPMS)‐negative. This mutant recovered α‐IPMS activity and a Leu + phenotype when transformed with a plasmid copy of YOR108w. These data and the sequence homology indicated that YOR108w is the structural gene for α‐IPMS II, responsible for the residual α‐IPMS activity found in a leu4Δ strain. The leu4Δ strain appeared to be very sensitive to the leucine analogue trifluoroleucine. In the absence of leucine, its growth was not much impaired in glucose but more on non‐fermentable carbon sources. Copyright © 2000 John Wiley & Sons, Ltd.