Biology subjects

Moretto, F.

Publications and source records attributed to Moretto, F..

2 recordsLinked to original sources

bioRxiv2019

Transcription levels of a long noncoding RNA orchestrate opposing regulatory and cell fate outcomes in yeast

Many long noncoding RNAs (lncRNAs) act in cis through transcription-coupled chromatin alterations that drive changes in local gene expression. How some cis-acting lncRNAs promote and others repress gene expression remains poorly understood. Here we report that in S. cerevisiae transcription levels of the lncRNA IRT2, located upstream in the promoter of the inducer of meiosis gene, regulate opposing chromatin and transcription states. Low IRT2 transcription displays enhancer RNA-like features. At these levels, IRT2 promotes histone exchange delivering acetylated histone H3 lysine 56 to chromatin thereby facilitating recruitment of a transcription factor and consequently activating transcription. Conversely, increasing IRT2 transcription enhances chromatin assembly and transcriptional repression. The opposing functions of IRT2 direct a regulatory circuit, which ensures that cells expressing opposite, but not one of either, mating-type loci enter meiosis. Our data demonstrate that the transcription levels of an lncRNA are key to controlling gene expression and cell fate outcomes.

biochemistry↗

bioRxiv2018

Repression of divergent noncoding transcription by a sequence-specific transcription factor

Many active eukaryotic gene promoters exhibit divergent noncoding transcription, but the mechanisms restricting expression of these transcripts are not well understood. Here we demonstrate how a sequence-specific transcription factor represses divergent noncoding transcription at highly expressed genes in yeast. We find that depletion of the transcription factor Rap1 induces noncoding transcription in a large fraction of Rap1 regulated gene promoters. Specifically, Rap1 prevents transcription initiation at cryptic promoters near its binding sites, which is uncoupled from transcription regulation in the protein-coding direction. We further provide evidence that Rap1 acts independently of chromatin-based mechanisms to repress cryptic or divergent transcription. Finally, we show that divergent transcription in the absence of Rap1 is elicited by the RSC chromatin remodeller. We propose that a sequence-specific transcription factor limits access of basal transcription machinery to regulatory elements and adjacent sequences that act as divergent cryptic promoters, thereby providing directionality towards productive transcription.

molecular biology↗