DNA cross-link repair 1B protein is a protein that in humans is encoded by the DCLRE1Bgene.[5]
DNA interstrand cross-links prevent strand separation, thereby physically blocking transcription, replication, and segregation of DNA. DCLRE1B is one of several evolutionarily conserved genes involved in repair of interstrand cross-links (Dronkert et al., 2000).[supplied by OMIM][5]
Function
The DCLRE1B/SNM1B/Apollo protein is a repair exonuclease that digests double-stranded and single-stranded DNA with a 5’ to 3’ directionality.[6]
In a human patient with Hoyeraal-Hreidarsson syndrome, a dominant negative mutation in the SNM1B/Apollo gene was discovered.[8] This mutation hampered the proper replication of telomeres, leading to major telomeric dysfunction and cellular senescence. SNM1B/Apollo protein appears to be a crucial factor in telomere maintenance, independent of its function in repairing DNA inter-strand crosslinks.[8]
Demuth I, Digweed M, Concannon P (2004). "Human SNM1B is required for normal cellular response to both DNA interstrand crosslink-inducing agents and ionizing radiation". Oncogene. 23 (53): 8611–8. doi:10.1038/sj.onc.1207895. PMID15467758. S2CID10082205.