In Saccharomyces cerevisiae, genes encoding maltose permeases and maltases are located in the telomeric regions of different chromosomes. The COMPASS methylation complex, which methylates lysine 4 on histone H3, controls silencing of telomeric regions. Yeast strains deleted for SWD1, SWD3, SDC1, SET1, BRE2 or SPP1, encoding components of the COMPASS complex, fermented a medium containing 22% maltose with noticeably higher attenuation than the wild type, resulting in production of up to 29% more ethanol. The least effective strain was spp1. Absence of COMPASS components had no effect on fermentation of media with 20% glucose, 20% sucrose or 16% maltose. Deletion of SWD3 resulted in higher amounts of MAL12 transcript, encoding maltase, at late stages of fermentation of 22% maltose. A similar effect was seen on maltase activity and maltose uptake capability. The lysine 4 residue of histone H3 was trimethylated in wild type cells at the late stages, while only low amounts of the dimethylated form were detected. Tri- and dimethylation of this residue were not detected in strains deleted for SWD1, SWD3, SET1, BRE2 or SDC1. Trimethylated lysine 4 was only apparent at early stages (48 and 96 hours) of the fermentation in a spp1 strain. This work indicates that the COMPASS complex represses expression of maltose utilization genes during late stages of fermentation of a high concentration of maltose.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|