Fig. 1

DNA double-strand repair protein C1D coordinates the exosome, condensin, and double-strand break (DSB) repair proteins in response to DSBs at highly transcribed genomic loci. Genomic instability at highly transcribed sites is common following RNA polymerase II transcription, and can be prevented by condensin-mediated stabilization of architectural integrity. RNA quality is also surveyed at these highly transcribed regions, particularly at sites hosting repetitive sequences. The formation of DSBs requires the prompt activation of repair pathways mediated by homologous recombination and non-homologous end joining machineries. When damage is unable to be repaired, the cells will induce apoptosis to prevent the cells from becoming carcinogenic. C1D protein physically interacts with proteins involved in all of these pathways, and we propose a coordinating role for the protein in maintaining genomic stability. Transcripts are indicated by blue lines; a defective transcript is indicated by a crooked blue line, which is being degraded by the exosome. DNA-PK DNA-dependent protein kinase, RNAPII RNA polymerase II