Genomic
analysis of the regulation of sorbic acid-inducible protein expression in
spoilage yeast.
Vasso Makrantoni,
Peter Coote
Biomolecular Sciences, University of St. Andrews, North Haugh, St. Andrews,
KY169ST, U.K. (vm14@st-andrews.ac.uk)
Saccharomyces
cerevisiae
can adapt and grow in the presence of weak acid preservatives, such as sorbic
acid, enabling them to spoil manufactured foods and beverages. Whilst we know
much about the mechanisms of adaptation to sorbic acid, little is known about
the stress-signalling pathway that induces this adaptive response. Thus, we
have screened the sorbic acid sensitivity of the deletion strains of all the
genes encoding regulatory proteins in S. cerevisiae, according to the MIPS
Protein Classes index, using the Research Genetics complete deletion set of S.
cerevisiae,
strain BY4741a. This included, 117 ORFs encoding protein kinases, 51 ORFs
encoding protein phosphatases and 182 ORFs encoding transcription factors.
Seven deletion mutants (vps15, dbf2, ctk1, bub1, war1, rox3, reg1) exhibited a sorbic acid
sensitive phenotype. To confirm that the sensitive phenotypes observed were
specifically due to deletion of each gene, we performed complementation studies
to rescue the sensitive phenotype. So far, we have successfully rescued the
sensitive phenotype of dbf2. Currently, we are using 2D PAGE-based
phospho-proteome analysis of dbf2 and vps15 deletion mutants to identify possible
changes in protein phosphorylation that may mediate sorbic acid adaptation.