Separating the impact of flocculation upon global gene transcription in a yeast Cyc8 mutant
The transcriptome from a S. cerevisiae tup1 deletion mutant was one of the first comprehensive yeast transcriptomes published. Subsequent transcriptomes from tup1 and cyc8 mutants firmly established the Tup1-Cyc8 complex as predominantly acting as a repressor of gene transcription. However, transcriptomes from tup1/cyc8 gene deletion or conditional mutants would all have been influenced by the striking flocculation phenotypes that these mutants display. In this study, we have separated the impact of flocculation from the transcriptome in a cyc8 conditional mutant to reveal those genes (i) subject solely to Cyc8p dependent regulation, (ii) regulated by flocculation only, and (iii) regulated by Cyc8p and further influenced by flocculation. We reveal an improved Cyc8p transcriptome that includes newly identified Cyc8p-regulated genes that were masked by the flocculation phenotype and excludes genes which were indirectly influenced by flocculation and not regulated by Cyc8p. Furthermore, we show evidence to suggest that flocculation exerts a complex and potentially dynamic influence upon global gene transcription. These data should be of interest to future studies into the mechanism of action of the Tup1-Cyc8 complex and to those involved in understanding the development of flocculation and its impact upon cell function. Overall design: We carried out RNA-Seq analysis to compare the transcriptomes of a flocculating Cyc8 conditional mutant (Flo+ Cyc8-AA) and a non-flocculating Cyc8 conditional mutant (Flo- Cyc8-AA)