Transcriptional regulator ATRX also known as ATP-dependent helicase ATRX, X-linked helicase II, or X-linked nuclear protein (XNP) is a protein that in humans is encoded by the ATRXgene.[1][2][3]
Transcriptional regulator ATRX contains an ATPase / helicase domain, and thus it belongs to the SWI/SNF family of chromatin remodeling proteins. ATRX is required for deposition of the histone variant H3.3 at telomeres and other genomic repeats.[4] These interactions are important for maintaining silencing at these sites.[5][6][7]
In addition, ATRX undergoes cell cycle-dependent phosphorylation, which regulates its nuclear matrix and chromatin association, and suggests its involvement in the gene regulation at interphase and chromosomal segregation in mitosis.[3]
Clinical significance
Inherited mutations
Inherited mutations of the ATRX gene are associated with an X-linked mental retardation (XLMR) syndrome most often accompanied by alpha-thalassemia (ATR-X) syndrome. These mutations have been shown to cause diverse changes in the pattern of DNA methylation, which may provide a link between chromatin remodeling, DNA methylation, and gene expression in developmental processes. Multiple alternatively spliced transcript variants encoding distinct isoforms have been reported. Female carriers may demonstrate skewed X chromosome inactivation.[3]
Somatic mutations
Acquired mutations in ATRX have been reported in a number of human cancers including pancreatic neuroendocrine tumours,[8] gliomas,[9] astrocytomas,[10] osteosarcomas,[11] and malignant pheochromocytomas.[12] There is a strong correlation between ATRX mutations and an Alternative Lengthening of Telomeres (ALT) phenotype in cancers.[8]
Interactions
ATRX forms a complex with DAXX which is an histone H3.3 chaperone.[13]
↑Stayton CL, Dabovic B, Gulisano M, Gecz J, Broccoli V, Giovanazzi S, et al. (November 1994). "Cloning and characterization of a new human Xq13 gene, encoding a putative helicase". Human Molecular Genetics. 3 (11): 1957–64. doi:10.1093/hmg/3.11.1957. PMID7874112.
↑Schwartzentruber J, Korshunov A, Liu XY, Jones DT, Pfaff E, Jacob K, et al. (January 2012). "Driver mutations in histone H3.3 and chromatin remodelling genes in paediatric glioblastoma". Nature. 482 (7384): 226–31. doi:10.1038/nature10833. PMID22286061.
↑Comino-Méndez, I (June 2016). "ATRX driver mutation in a composite malignant pheochromocytoma". Cancer Genetics. 209 (6): 272. doi:10.1016/j.cancergen.2016.04.058.
↑Cardoso C, Timsit S, Villard L, Khrestchatisky M, Fontès M, Colleaux L (April 1998). "Specific interaction between the XNP/ATR-X gene product and the SET domain of the human EZH2 protein". Human Molecular Genetics. 7 (4): 679–84. doi:10.1093/hmg/7.4.679. PMID9499421.
Further reading
Mulley JC, Kerr B, Stevenson R, Lubs H (1992). "Nomenclature guidelines for X-linked mental retardation". American Journal of Medical Genetics. 43 (1–2): 383–91. doi:10.1002/ajmg.1320430159. PMID1605216.
Tang P, Park DJ, Marshall Graves JA, Harley VR (September 2004). "ATRX and sex differentiation". Trends in Endocrinology and Metabolism. 15 (7): 339–44. doi:10.1016/j.tem.2004.07.006. PMID15350606.
Forget BG (March 2006). "De novo and acquired forms of alpha thalassemia". Current Hematology Reports. 5 (1): 11–4. PMID16537041.
Adès LC, Kerr B, Turner G, Wise G (September 1991). "Smith-Fineman-Myers syndrome in two brothers". American Journal of Medical Genetics. 40 (4): 467–70. doi:10.1002/ajmg.1320400419. PMID1684092.
Sutherland GR, Gedeon AK, Haan EA, Woodroffe P, Mulley JC (1988). "Linkage studies with the gene for an X-linked syndrome of mental retardation, microcephaly and spastic diplegia (MRX2)". American Journal of Medical Genetics. 30 (1–2): 493–508. doi:10.1002/ajmg.1320300152. PMID3177467.
Gibbons RJ, Picketts DJ, Villard L, Higgs DR (March 1995). "Mutations in a putative global transcriptional regulator cause X-linked mental retardation with alpha-thalassemia (ATR-X syndrome)". Cell. 80 (6): 837–45. doi:10.1016/0092-8674(95)90287-2. PMID7697714.
Wang LH, Collins A, Lawrence S, Keats BJ, Morton NE (August 1994). "Integration of gene maps: chromosome X". Genomics. 22 (3): 590–604. doi:10.1006/geno.1994.1432. PMID8001970.
Gecz J, Pollard H, Consalez G, Villard L, Stayton C, Millasseau P, Khrestchatisky M, Fontes M (January 1994). "Cloning and expression of the murine homologue of a putative human X-linked nuclear protein gene closely linked to PGK1 in Xq13.3". Human Molecular Genetics. 3 (1): 39–44. doi:10.1093/hmg/3.1.39. PMID8162050.
Villard L, Gecz J, Mattéi JF, Fontés M, Saugier-Veber P, Munnich A, Lyonnet S (April 1996). "XNP mutation in a large family with Juberg-Marsidi syndrome". Nature Genetics. 12 (4): 359–60. doi:10.1038/ng0496-359. PMID8630485.
Bonaldo MF, Lennon G, Soares MB (September 1996). "Normalization and subtraction: two approaches to facilitate gene discovery". Genome Research. 6 (9): 791–806. doi:10.1101/gr.6.9.791. PMID8889548.
Picketts DJ, Higgs DR, Bachoo S, Blake DJ, Quarrell OW, Gibbons RJ (December 1996). "ATRX encodes a novel member of the SNF2 family of proteins: mutations point to a common mechanism underlying the ATR-X syndrome". Human Molecular Genetics. 5 (12): 1899–907. doi:10.1093/hmg/5.12.1899. PMID8968741.
Villard L, Lacombe D, Fontés M (1997). "A point mutation in the XNP gene, associated with an ATR-X phenotype without alpha-thalassemia". European Journal of Human Genetics. 4 (6): 316–20. doi:10.1159/000472225. PMID9043863.
Villard L, Lossi AM, Cardoso C, Proud V, Chiaroni P, Colleaux L, Schwartz C, Fontés M (July 1997). "Determination of the genomic structure of the XNP/ATRX gene encoding a potential zinc finger helicase". Genomics. 43 (2): 149–55. doi:10.1006/geno.1997.4793. PMID9244431.
Gibbons RJ, Bachoo S, Picketts DJ, Aftimos S, Asenbauer B, Bergoffen J, Berry SA, Dahl N, Fryer A, Keppler K, Kurosawa K, Levin ML, Masuno M, Neri G, Pierpont ME, Slaney SF, Higgs DR (October 1997). "Mutations in transcriptional regulator ATRX establish the functional significance of a PHD-like domain". Nature Genetics. 17 (2): 146–8. doi:10.1038/ng1097-146. PMID9326931.
Cardoso C, Timsit S, Villard L, Khrestchatisky M, Fontès M, Colleaux L (April 1998). "Specific interaction between the XNP/ATR-X gene product and the SET domain of the human EZH2 protein". Human Molecular Genetics. 7 (4): 679–84. doi:10.1093/hmg/7.4.679. PMID9499421.