The Mot1 ATPase and Spt16 Histone Chaperone Cooperatively Regulate Transcription

Mot1 is a conserved and essential Swi2/Snf2 ATPase that can remove TATA-binding protein (TBP) from DNA using ATP hydrolysis, and in so doing exerts global effects on transcription. Spt16 is also essential and functions globally in transcriptional regulation as a component of the FACT histone chaperone complex. Here we demonstrate that Mot1 and Spt16 regulate a largely overlapping set of genes in Saccharomyces cerevisiae. As expected, Mot1 was found to control TBP levels at co-regulated promoters. In contrast, Spt16 did not affect TBP recruitment. Interestingly, Mot1 was required for Spt16 recruitment to co-activated promoters. In contrast, Spt16 levels in gene coding regions were unaffected by Mot1 as well as RNA polymerase II density. The co-localization of Mot1 and Spt16 at promoters and the broad overlap in the sets of genes they control is consistent with physical and genetic interactions between them. The data support a model in which these factors participate in a regulatory pathway in which Mot1 acts upstream of Spt16. Tiling arrays covering the entirety of the S.cerevisiae genome were used to identify the effects of Mot1 and Spt16 on RNA expression genome-wide. All samples were done in biological duplicates. The average signal from the spt16-197 samples was compared to the SPT16-WT to determine changes in expression. The average signal from the double mutant mot1-42 spt16-197 was compared to both SPT16-WT and MOT1-WT. The MOT1-WT data was previously published by our lab and is available at GEO accession GSM456548. Comparisons were made from our Spt16 dataset to the previously published MOT1-WT and mot1-42 data, and the entire study is available at GEO accession GSE18283. Differential RNA (spt16-197/SPT16): spt16-197_over_SPT16-WT.bar Differential RNA (mot1-42 spt16-197/SPT16): dbl_mut_over_SPT16-WT.bar Differential RNA (mot1-42 spt16-197/MOT1): dbl_mut_over_MOT1-WT.bar