Most DNA in the genomes of higher organisms does not code for proteins. RNA Polymerase II (Pol II) transcribes non-coding DNA into long non-coding RNAs (lncRNAs), but biological roles of lncRNA are unclear. Researchers at the University of Copenhagen found that mutations in the yeast lncRNA CUT60 result in poor growth. Defective termination of CUT60 transcription causes read-through transcription across the ATP16 gene promoter. Read-through transcription localizes chromatin signatures associated with Pol II elongation to the ATP16 promoter. The act of Pol II elongation across this promoter represses functional ATP16 expression by a Transcriptional Interference (TI) mechanism. Atp16p function in the mitochondrial ATP-synthase complex promotes mitochondrial DNA stability. ATP16 repression by TI through inefficient termination of CUT60 therefore triggers mitochondrial genome loss. These results expand the functional and mechanistic implications of non-coding DNA in eukaryotes by highlighting termination of nuclear lncRNA transcription as mechanism to stabilize an organellar genome.
du Mee DJM, Ivanov M, Parker JP, Buratowski S, Marquardt S. (2018) Efficient termination of nuclear lncRNA transcription promotes mitochondrial genome maintenance. Elife e31989. [article]
Tagged with: chromatin chromosomes evolutionary biology genes Genome Stability genomics lncrna Pervasive transcription RNA polymerase II S. cerevisiae Transcriptional Interference University of Copenhagen