Role of genome guardian proteins in transcriptional elongation.

Maintaining genomic integrity is vital for cell survival and homeostasis. Mutations in critical genes in germ-line and somatic cells are often implicated with the onset or progression of diseases. DNA repair enzymes thus take important roles as guardians of the genome in the cell. Besides the known function to repair DNA damage, recent findings indicate that DNA repair enzymes regulate the transcription of protein-coding and noncoding RNA genes. In particular, a novel role of DNA damage response signaling has been identified in the regulation of transcriptional elongation. Topoisomerases-mediated DNA breaks appear important for the regulation. In this review, recent findings of these DNA break- and repair-associated enzymes in transcription and potential roles of transcriptional activation-coupled DNA breaks are discussed.