末端脫氧核苷酸轉移酶

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末端脫氧核苷酸轉移酶(Terminal deoxynucleotidyl transferasTdT末端轉移酶),是一種特殊的DNA聚合酶,顯示出未成熟的、"前B","前T淋巴細胞"和"急性淋巴性白血病/淋巴瘤細胞"。"末端轉移酶"於"抗體基因重組時"加上N核苷酸(N-nucleotide)至V(D)J外顯子上,能夠形成連接多樣性(Junctional diversity)的現象。在人類中,末端轉移酶是由DNTT基因來編碼。 [1][2]

TdT不存在於"胎肝造血幹細胞"上,而在胎兒期明顯的損害B細胞之連接多樣性。[3]

目錄

功能

"末端轉移酶"催化的加上核苷酸至DNA分子3'末端。不像大多數的DNA聚合酶,它不需要一個模板。這種酶的優選底物3'突出端,但它也可以添加"核苷酸"(nucleotifes)至"鈍末端"(blunt end)或"凹陷的3'末端"(recessed 3' end)。鈷是一種必要的輔因子,但是在酶催化後反應在的鎂(Mg)及錳(Mn)施用"體外"(in vitro)。

使用

末端轉移酶在分子生物學中的應用。它可以被用來在cDNA末端的快速擴增(RACE)中來添加"核苷酸"(nucleotide),然後可以用來作為在後續PCR的"引子"(primer)的模板。它也可以用於添加標記放射性同位素的核苷酸,例如在TUNEL檢測(末端脫氧核苷酸轉移酶"dUTP缺口末端標記"(dUTP Nick End Labeling)),用於細胞凋亡的示範(其中的標記,在某種程度上,通過片段化DNA來進行)。也可用於治療"急性淋巴性白血病"診斷之"免疫熒光測定"(immuno-fluorescence)。[4]

免疫組織化學中,抗體TdT酶可用於顯示未成熟的T細胞和B細胞以及多能的"造血(Haematopoiesis)幹細胞"的存在,其具有抗原,而成熟的淋巴樣細胞總是呈"TdT陰性"。而末端轉移酶陽性的細胞中發現少量的健康淋巴結扁桃體急性淋巴細胞白血病的惡性細胞也呈"TdT陽性",而抗體,因此可以被用來作為面板診斷及區別這種疾病的一部分,比如,"初發期的小細胞腫瘤"(small cell tumours of childhood)。[5]

參見

注釋

  1. Isobe M, Huebner K, Erikson J, Peterson RC, Bollum FJ, Chang LM, Croce CM. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC390648/ Chromosome localization of the gene for human terminal deoxynucleotidyltransferase to region 10q23-q25]. Proc. Natl. Acad. Sci. U.S.A.. September 1985, 82 (17): 5836–40. doi:10.1073/pnas.82.17.5836. PMID 3862101. PMC 390648. 
  2. Yang-Feng TL, Landau NR, Baltimore D, Francke U. The terminal deoxynucleotidyltransferase gene is located on human chromosome 10 (10q23-q24) and on mouse chromosome 19. Cytogenet. Cell Genet.. 1986, 43 (3-4): 121–6. doi:10.1159/000132309. PMID 3467897. 
  3. Hardy, Richard. Chapter 7: B Lymphocyte Development and Biology//Paul, William. Fundamental Immunology (Book). 6th. Philadelphia: Lippincott Williams & Wilkins. 2008: pp. 237–269. ISBN 0-7817-6519-6. 
  4. Faber J, Kantarjian H, Roberts MW, Keating M, Freireich E, Albitar M. Terminal deoxynucleotidyl transferase-negative acute lymphoblastic leukemia. Arch. Pathol. Lab. Med.. January 2000, 124 (1): 92–7. PMID 10629138. 
  5. Leong, Anthony S-Y; Cooper, Kumarason; Leong, F Joel W-M. Manual of Diagnostic Cytology. 2. Greenwich Medical Media, Ltd.. 2003: pp. 413–414. ISBN 1-84110-100-1. 

Further reading

  • O'Malley DP, Orazi A. Terminal deoxynucleotidyl transferase-positive cells in spleen, appendix and branchial cleft cysts in pediatric patients.. Haematologica. 2006, 91 (8): 1139–40. PMID 16885057. 
  • Yamashita N, Shimazaki N, Ibe S, et al.. Terminal deoxynucleotidyltransferase directly interacts with a novel nuclear protein that is homologous to p65.. Genes Cells. 2001, 6 (7): 641–52. doi:10.1046/j.1365-2443.2001.00449.x. PMID 11473582. 
  • Chang LM, Bollum FJ. Molecular biology of terminal transferase.. CRC Crit. Rev. Biochem.. 1986, 21 (1): 27–52. doi:10.3109/10409238609113608. PMID 3524991. 
  • Maezawa S, Hayano T, Koiwai K, et al.. Bood POZ containing gene type 2 is a human counterpart of yeast Btb3p and promotes the degradation of terminal deoxynucleotidyltransferase.. Genes Cells. 2008, 13 (5): 439–57. doi:10.1111/j.1365-2443.2008.01179.x. PMID 18429817. 
  • Taplin ME, Frantz ME, Canning C, et al.. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC1384108/ Evidence against T-cell development in the adult human intestinal mucosa based upon lack of terminal deoxynucleotidyltransferase expression.]. Immunology. 1996, 87 (3): 402–7. doi:10.1046/j.1365-2567.1996.496571.x. PMID 8778025. PMC 1384108. 
  • Grupe A, Li Y, Rowland C, et al.. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC1380225/ A scan of chromosome 10 identifies a novel locus showing strong association with late-onset Alzheimer disease.]. Am. J. Hum. Genet.. 2006, 78 (1): 78–88. doi:10.1086/498851. PMID 16385451. PMC 1380225. 
  • Dworzak MN, Fritsch G, Fröschl G, et al.. Four-color flow cytometric investigation of terminal deoxynucleotidyl transferase-positive lymphoid precursors in pediatric bone marrow: CD79a expression precedes CD19 in early B-cell ontogeny.. Blood. 1998, 92 (9): 3203–9. PMID 9787156. 
  • Fujita K, Shimazaki N, Ohta Y, et al.. Terminal deoxynucleotidyltransferase forms a ternary complex with a novel chromatin remodeling protein with 82 kDa and core histone.. Genes Cells. 2003, 8 (6): 559–71. doi:10.1046/j.1365-2443.2003.00656.x. PMID 12786946. 
  • Kubota T, Maezawa S, Koiwai K, et al.. Identification of functional domains in TdIF1 and its inhibitory mechanism for TdT activity.. Genes Cells. 2007, 12 (8): 941–59. doi:10.1111/j.1365-2443.2007.01105.x. PMID 17663723. 
  • Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, et al.. Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library.. Gene. 1997, 200 (1-2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID 9373149. 
  • Bridges SL. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC2230400/ Frequent N addition and clonal relatedness among immunoglobulin lambda light chains expressed in rheumatoid arthritis synovia and PBL, and the influence of V lambda gene segment utilization on CDR3 length.]. Mol. Med.. 1998, 4 (8): 525–53. PMID 9742508. PMC 2230400. 
  • Liu L, McGavran L, Lovell MA, et al.. Nonpositive terminal deoxynucleotidyl transferase in pediatric precursor B-lymphoblastic leukemia.. Am. J. Clin. Pathol.. 2004, 121 (6): 810–5. doi:10.1309/QD18-PPV1-NH3T-EUTF. PMID 15198352. 
  • Yang B, Gathy KN, Coleman MS. Mutational analysis of residues in the nucleotide binding domain of human terminal deoxynucleotidyl transferase.. J. Biol. Chem.. 1994, 269 (16): 11859–68. PMID 8163485. 
  • Gerhard DS, Wagner L, Feingold EA, et al.. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC528928/ The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).]. Genome Res.. 2004, 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMID 15489334. PMC 528928. 
  • Thai TH, Kearney JF. Distinct and opposite activities of human terminal deoxynucleotidyltransferase splice variants.. J. Immunol.. 2004, 173 (6): 4009–19. PMID 15356150. 
  • Shimazaki N, Fujita K, Koiwai O. [Expression and function of terminal deoxynucleotidyl-transferase and discovery of novel DNA polymerase mu]. Seikagaku. 2002, 74 (3): 227–32. PMID 11974916. 
  • Mahajan KN, Mitchell BS. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC196874/ Role of human Pso4 in mammalian DNA repair and association with terminal deoxynucleotidyl transferase.]. Proc. Natl. Acad. Sci. U.S.A.. 2003, 100 (19): 10746–51. doi:10.1073/pnas.1631060100. PMID 12960389. PMC 196874. 
  • Strausberg RL, Feingold EA, Grouse LH, et al.. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC139241/ Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.]. Proc. Natl. Acad. Sci. U.S.A.. 2002, 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMID 12477932. PMC 139241. 
  • Mahajan KN, Gangi-Peterson L, Sorscher DH, et al.. [http//www.ncbi.nlm.nih.gov/pmc/articles/PMC24167/ Association of terminal deoxynucleotidyl transferase with Ku.]. Proc. Natl. Acad. Sci. U.S.A.. 1999, 96 (24): 13926–31. doi:10.1073/pnas.96.24.13926. PMID 10570175. PMC 24167. 
  • Ibe S, Fujita K, Toyomoto T, et al.. Terminal deoxynucleotidyltransferase is negatively regulated by direct interaction with proliferating cell nuclear antigen.. Genes Cells. 2001, 6 (9): 815–24. doi:10.1046/j.1365-2443.2001.00460.x. PMID 11554927. 

外部連結

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