长末端重复序列

长末端重复序列（Long terminal repeat，简称LTR）是真核生物基因组中某些反转录转座子、内源性反转录病毒或反转录病毒序列两端长数百bp的成对序列，最早由A.P. Czernilofsky和约翰·沙恩（英语：John Shine）于1980年在家禽白血病病毒（英语：Avian sarcoma leukosis virus）序列中发现^[1]。此类元件通常可编码反转录酶与整合酶以将其自身序列复制后再插入基因组中，人类基因组中即有5%至8%的序列为带有长末端重复序列的内源性反转录病毒^[2]^[3]。在病毒插入基因组时成对的长末端重复序列应为相同，并随时间逐渐发生变异，因此成对长末端重复序列的差异可被用于分子演化研究以测定该元件插入基因组的时间，但基因转换等机制可能影响此方法测定年代的结果^[4]。

以HIV-1为例，其长末端重复序列长634bp，可细分为U3、R与U5三个区域，在宿主基因组中5端的长末端重复序列可作为启动子与多种转录因子结合，3端的长末端序列则可作为切割与多腺苷酸化的讯号，此外还编码一辅助蛋白Nef^[5]。

参考文献

^ Czernilofsky, A.P.; DeLorbe, W.; Swanstrom, R.; Varmus, H.E.; Bishop, J.M.; Tischer, E.; Goodman, H.M. The nucleotide sequence of an untranslated but conserved domain at the 3′ end of the avian sarcoma virus genome. Nucleic Acids Research. 1980, 8 (13) [2022-10-25]. ISSN 0305-1048. PMC 324138  . PMID 6253899. doi:10.1093/nar/8.13.2967. （原始内容存档于2017-02-03）（英语）.
^ Belshaw, Robert; Pereira, Vini; Katzourakis, Aris; Talbot, Gillian; Pačes, Jan; Burt, Austin; Tristem, Michael. Long-term reinfection of the human genome by endogenous retroviruses. Proceedings of the National Academy of Sciences. 2004-04-06, 101 (14) [2022-10-25]. Bibcode:2004PNAS..101.4894B. ISSN 0027-8424. PMC 387345  . PMID 15044706. doi:10.1073/pnas.0307800101. （原始内容存档于2022-05-01）（英语）.
^ Nelson, P N; Hooley, P; Roden, D; Davari Ejtehadi, H; Rylance, P; Warren, P; Martin, J; Murray, P G. Human endogenous retroviruses: transposable elements with potential?. Clinical and Experimental Immunology. 2004-08-31, 138 (1) [2022-10-25]. ISSN 1365-2249. PMC 1809191  . PMID 15373898. doi:10.1111/j.1365-2249.2004.02592.x. （原始内容存档于2022-12-26）（英语）.
^ Hayward, Alexander. Origin of the retroviruses: when, where, and how?. Current Opinion in Virology. Animal models for viral diseases • Paleovirology. 2017-08-01, 25 [2022-10-25]. ISSN 1879-6257. PMC 5962544  . PMID 28672160. doi:10.1016/j.coviro.2017.06.006. （原始内容存档于2022-10-28）（英语）.
^ Krebs, Fred C.; Hogan, Tricia H.; Quiterio, Shane; Gartner, Suzanne; Wigdahl, Brian. Lentiviral LTR-directed Expression, Sequence Variation, and Disease Pathogenesis (PDF). Kuiken, C; Foley, B; B; Marx, P; McCutchan, F; Mellors, JW; Wolinsky, S; Korber, B (编). HIV Sequence Compendium 2001. Los Alamos, NM: Theoretical Biology and Biophysics Group, Los Alamos National Laboratory. 2001: 29–70 [2021-05-11]. （原始内容存档 (PDF)于2020-08-06）.

[Czernilofsky1980-1] Czernilofsky, A.P.; DeLorbe, W.; Swanstrom, R.; Varmus, H.E.; Bishop, J.M.; Tischer, E.; Goodman, H.M. The nucleotide sequence of an untranslated but conserved domain at the 3′ end of the avian sarcoma virus genome. Nucleic Acids Research. 1980, 8 (13) [2022-10-25]. ISSN 0305-1048. PMC 324138  . PMID 6253899. doi:10.1093/nar/8.13.2967. （原始内容存档于2017-02-03）（英语）.

[Belshaw2004-2] Belshaw, Robert; Pereira, Vini; Katzourakis, Aris; Talbot, Gillian; Pačes, Jan; Burt, Austin; Tristem, Michael. Long-term reinfection of the human genome by endogenous retroviruses. Proceedings of the National Academy of Sciences. 2004-04-06, 101 (14) [2022-10-25]. Bibcode:2004PNAS..101.4894B. ISSN 0027-8424. PMC 387345  . PMID 15044706. doi:10.1073/pnas.0307800101. （原始内容存档于2022-05-01）（英语）.

[3] Nelson, P N; Hooley, P; Roden, D; Davari Ejtehadi, H; Rylance, P; Warren, P; Martin, J; Murray, P G. Human endogenous retroviruses: transposable elements with potential?. Clinical and Experimental Immunology. 2004-08-31, 138 (1) [2022-10-25]. ISSN 1365-2249. PMC 1809191  . PMID 15373898. doi:10.1111/j.1365-2249.2004.02592.x. （原始内容存档于2022-12-26）（英语）.

[4] Hayward, Alexander. Origin of the retroviruses: when, where, and how?. Current Opinion in Virology. Animal models for viral diseases • Paleovirology. 2017-08-01, 25 [2022-10-25]. ISSN 1879-6257. PMC 5962544  . PMID 28672160. doi:10.1016/j.coviro.2017.06.006. （原始内容存档于2022-10-28）（英语）.

[5] Krebs, Fred C.; Hogan, Tricia H.; Quiterio, Shane; Gartner, Suzanne; Wigdahl, Brian. Lentiviral LTR-directed Expression, Sequence Variation, and Disease Pathogenesis (PDF). Kuiken, C; Foley, B; B; Marx, P; McCutchan, F; Mellors, JW; Wolinsky, S; Korber, B (编). HIV Sequence Compendium 2001. Los Alamos, NM: Theoretical Biology and Biophysics Group, Los Alamos National Laboratory. 2001: 29–70 [2021-05-11]. （原始内容存档 (PDF)于2020-08-06）.

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