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

Many long noncoding RNAs (lncRNAs) act through transcription-coupled chromatin alterations that drive changes in local gene expression. How some -acting lncRNAs promote and others repress gene expression remains poorly understood. Here we report that in transcription levels of the lncRNA , located upstream in the promoter of the inducer of meiosis gene, regulate opposing chromatin and transcription states. Low transcription displays enhancer RNA-like features. At these levels, promotes histone exchange delivering acetylated histone H3 lysine 56 to chromatin thereby facilitating recruitment of a transcription factor and consequently activating transcription. Conversely, increasing transcription enhances chromatin assembly and transcriptional repression. The opposing functions of 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.