5-羟甲基胞嘧啶

5-羟甲基胞嘧啶（5-Hydroxymethylcytosine，簡稱5hmc）是生物DNA中由胞嘧啶（C）衍生而來的一種核鹼基，其化學式為C5H7N3O2，可能有調控基因表現的功能，為表觀遺傳學上重要的鹼基。5hmc最早於1952年在噬菌體DNA中被發現，可能為噬菌體避免被細菌限制酶切割的一種機制，有些細菌則演化出可切割含5hmc序列的限制酶（如PvuRts1I）。1972年此鹼基首度在哺乳類DNA中被發現，2009年有研究在人類與小鼠的腦組織DNA和胚胎幹細胞的DNA中發現5hmc，目前已知大多數的哺乳類細胞中可能均含有5hmc，但含量不一，在中樞神經系統的神經元及原生殖細胞中較多，且含量可能因年齡而變化。5hmc的具體功能尚不清楚，可能與DNA去甲基化（英语：DNA demethylation）（促進基因表現）有關。 2012年，芝加哥大學的何川實驗室發表了可對基因組中5hmc進行測序的技術TAB-seq。 分子与细胞生物学主题 5-Hydroxymethylcytosine. nextbio.com. [2022-01-21]. （原始内容存档于2017-09-04）.  Warren, RA. Modified bases in bacteriophage DNAs. Annu. Rev. Microbiol. 1980, 34: 137–158. PMID 7002022. doi:10.1146/annurev.mi.34.100180.001033.  Wyatt, GR; Cohen, SS. A new pyrimidine base from bacteriophage nucleic acids. Nature. December 1952, 170 (4338): 1072–1073. Bibcode:1952Natur.170.1072W. PMID 13013321. S2CID 4277592. doi:10.1038/1701072a0.  Borgaro, JG; Zhu, Z. Characterization of the 5-hydroxymethylcytosine-specific DNA restriction endonucleases.. Nucleic Acids Research. April 2013, 41 (7): 4198–206. PMC 3627594 . PMID 23482393. doi:10.1093/nar/gkt102.  Kriaucionis, S; Heintz, N. The nuclear DNA base 5-hydroxymethylcytosine is present in Purkinje neurons and the brain. Science. May 2009, 324 (5929): 929–930. Bibcode:2009Sci...324..929K. PMC 3263819 . PMID 19372393. doi:10.1126/science.1169786.  Tahiliani M; et al. Conversion of 5-methylcytosine to 5-hydroxymethylcytosine in mammalian DNA by MLL partner TET1 (PDF). Science. May 2009, 324 (5929): 930–935 [2022-01-21]. Bibcode:2009Sci...324..930T. PMC 2715015 . PMID 19372391. doi:10.1126/science.1170116. （原始内容 (PDF)存档于2022-01-21）.  Münzel M; et al. Quantification of the Sixth DNA Base Hydroxymethylcytosine in the Brain. Angew. Chem. Int. Ed. July 2010, 49 (31): 5375–5377. PMID 20583021. doi:10.1002/anie.201002033.  Szwagierczak A; et al. Sensitive Enzymatic Quantification of 5-Hydroxymethylcytosine in Genomic DNA. Nucleic Acids Res. October 2010, 38 (19): e181. PMC 2965258 . PMID 20685817. doi:10.1093/nar/gkq684.  Globisch D; et al. Croft, Anna Kristina , 编. Tissue Distribution of 5-Hydroxymethylcytosine and Search for Active Demethylation Intermediates. PLOS ONE. December 2010, 5 (12): e15367. Bibcode:2010PLoSO...515367G. PMC 3009720 . PMID 21203455. doi:10.1371/journal.pone.0015367 .  Hackett, JA; Sengupta, R; Zylicz, JJ; Murakami, K; Lee, C; Down, T; Surani, MA. Germline DNA demethylation dynamics and imprint erasure through 5-hydroxymethylcytosine. Science. 2012-12-06, 339 (6118): 448–52. PMC 3847602 . PMID 23223451. doi:10.1126/science.1229277.  Song C-X; et al. Selective chemical labeling reveals the genome-wide distribution of 5-hydroxymethylcytosine. Nat. Biotechnol. December 2010, 29 (1): 68–72. PMC 3107705 . PMID 21151123. doi:10.1038/nbt.1732.  Guo, Junjie U.; Su, Yijing; Zhong, Chun; Ming, Guo-li; Song, Hongjun. Hydroxylation of 5-Methylcytosine by TET1 Promotes Active DNA Demethylation in the Adult Brain. Cell. 1 April 2011, 145 (3): 423–434. PMC 3088758 . PMID 21496894. doi:10.1016/j.cell.2011.03.022.  Mellén, M; Ayata, P; Heintz, N. 5-hydroxymethylcytosine accumulation in postmitotic neurons results in functional demethylation of expressed genes. Proc Natl Acad Sci U S A. Sep 2017, 114 (37): E7812–E7821. PMC 5604027 . PMID 28847947. doi:10.1073/pnas.1708044114 .  Yu M, Hon GC, Szulwach KE, Song CX, Zhang L, Kim A, Li XK, Dai Q, Shen Y, Park B, Min JH, Jin P, Ren B, He C. Base-resolution analysis of 5-hydroxymethylcytosine in the mammalian genome.. Cell. June 2012, 149 (6): 1368–1380. PMC 3589129 . PMID 22608086. doi:10.1016/j.cell.2012.04.027.  Song CX, Szulwach KE, Fu Y, Dai Q, Yi C, Li X, Li Y, Chen CH, Zhang W, Jian X, Wang J, Zhang L, Looney TJ, Zhang B, Godley LA, Hicks LM, Lahn BT, Jin P, He C. Selective chemical labeling reveals the genome-wide distribution of 5-hydroxymethylcytosine. Nat. Biotechnol. 2011, 29 (1): 68–72. PMC 3107705 . PMID 21151123. doi:10.1038/nbt.1732.