| First Author | Tubbs AT | Year | 2014 |
| Journal | Mol Cell Biol | Volume | 34 |
| Issue | 15 | Pages | 2811-21 |
| PubMed ID | 24842905 | Mgi Jnum | J:223682 |
| Mgi Id | MGI:5660069 | Doi | 10.1128/MCB.00441-14 |
| Citation | Tubbs AT, et al. (2014) KAP-1 promotes resection of broken DNA ends not protected by gamma-H2AX and 53BP1 in G(1)-phase lymphocytes. Mol Cell Biol 34(15):2811-21 |
| abstractText | The resection of broken DNA ends is required for DNA double-strand break (DSB) repair by homologous recombination (HR) but can inhibit normal repair by nonhomologous end joining (NHEJ), the main DSB repair pathway in G1-phase cells. Antigen receptor gene assembly proceeds through DNA DSB intermediates generated in G1-phase lymphocytes by the RAG endonuclease. These DSBs activate ATM, which phosphorylates H2AX, forming gamma-H2AX in flanking chromatin. gamma-H2AX prevents CtIP from initiating resection of RAG DSBs. Whether there are additional proteins required to promote resection of these DNA ends is not known. KRAB-associated protein 1 (KAP-1) (TRIM28) is a transcriptional repressor that modulates chromatin structure and has been implicated in the repair of DNA DSBs in heterochromatin. Here, we show that in murine G1-phase lymphocytes, KAP-1 promotes resection of DSBs that are not protected by H2AX and its downstream effector 53BP1. In these murine cells, KAP-1 activity in DNA end resection is attenuated by a single-amino-acid change that reflects a KAP-1 polymorphism between primates and other mammalian species. These findings establish KAP-1 as a component of the machinery that can resect DNA ends in G1-phase cells and suggest that there may be species-specific features to this activity. |
