DNA repair protein complementing XP-G cells is a protein that in humans is encoded by the ERCC5gene.[5][6]
Function
Excision repair cross-complementing rodent repair deficiency, complementation group 5 (xeroderma pigmentosum, complementation group G) is involved in excision repair of UV-induced DNA damage. Mutations cause Cockayne syndrome, which is characterized by severe growth defects, mental retardation, and cachexia. Multiple alternatively spliced transcript variants encoding distinct isoforms have been described, but the biological validity of all variants has not been determined.[6]
Mutational defects in the Ercc5(Xpg) gene can cause either the cancer-prone condition xeroderma pigmentosum (XP) alone, or in combination with the severe neurodevelopmental disorder Cockayne syndrome (CS) or the infantile lethal cerebro-oculo-facio-skeletal syndrome.[8]
Mouse model
An Ercc5(Xpg) mutant mouse model presented features of premature aging including cachexia and osteoporosis with pronounced degenerative phenotypes in both liver and brain.[8] These mutant mice developed a multi-system premature aging degenerative phenotype that appears to strengthen the link between DNA damage and aging.[8] (see DNA damage theory of aging).
Dietary restriction, which extends lifespan of wild-type mice, also substantially increased the lifespan of Ercc5(Xpg) mutant mice.[9] Dietary restriction of the mutant mice, while delaying aging, also appeared to slow the accumulation of genome wide DNA damage and to preserve transcriptional output, thus contributing to improved cell viability.
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Samec S, Jones TA, Corlet J, Scherly D, Sheer D, Wood RD, Clarkson SG (May 1994). "The human gene for xeroderma pigmentosum complementation group G (XPG) maps to 13q33 by fluorescence in situ hybridization". Genomics. 21 (1): 283–5. doi:10.1006/geno.1994.1261. PMID8088806.
^Drury S, Boustred C, Tekman M, Stanescu H, Kleta R, Lench N, Chitty LS, Scott RH (July 2014). "A novel homozygous ERCC5 truncating mutation in a family with prenatal arthrogryposis--further evidence of genotype-phenotype correlation". American Journal of Medical Genetics. Part A. 164A (7): 1777–83. doi:10.1002/ajmg.a.36506. PMID24700531. S2CID8023991.
^Iyer N, Reagan MS, Wu KJ, Canagarajah B, Friedberg EC (February 1996). "Interactions involving the human RNA polymerase II transcription/nucleotide excision repair complex TFIIH, the nucleotide excision repair protein XPG, and Cockayne syndrome group B (CSB) protein". Biochemistry. 35 (7): 2157–67. doi:10.1021/bi9524124. PMID8652557.
Shiomi T, Harada Y, Saito T, Shiomi N, Okuno Y, Yamaizumi M (March 1994). "An ERCC5 gene with homology to yeast RAD2 is involved in group G xeroderma pigmentosum". Mutation Research. 314 (2): 167–75. doi:10.1016/0921-8777(94)90080-9. PMID7510366.
Lehmann AR, Bootsma D, Clarkson SG, Cleaver JE, McAlpine PJ, Tanaka K, Thompson LH, Wood RD (July 1994). "Nomenclature of human DNA repair genes". Mutation Research. 315 (1): 41–2. doi:10.1016/0921-8777(94)90026-4. PMID7517009.
Scherly D, Nouspikel T, Corlet J, Ucla C, Bairoch A, Clarkson SG (May 1993). "Complementation of the DNA repair defect in xeroderma pigmentosum group G cells by a human cDNA related to yeast RAD2". Nature. 363 (6425): 182–5. Bibcode:1993Natur.363..182S. doi:10.1038/363182a0. PMID8483504. S2CID9713824.
Iyer N, Reagan MS, Wu KJ, Canagarajah B, Friedberg EC (February 1996). "Interactions involving the human RNA polymerase II transcription/nucleotide excision repair complex TFIIH, the nucleotide excision repair protein XPG, and Cockayne syndrome group B (CSB) protein". Biochemistry. 35 (7): 2157–67. doi:10.1021/bi9524124. PMID8652557.