Retrotransposon

Retrotransposons (also called Class I transposable elements) are mobile elements which move in the host genome by converting their transcribed RNA into DNA through the reverse transcription.^[1] Thus, they differ from Class II transposable elements, or DNA transposons, in utilizing an RNA intermediate for the transposition and leaving the transposition donor site unchanged.^[2]

Through reverse transcription, retrotransposons amplify themselves quickly to become abundant in eukaryotic genomes such as maize (49–78%)^[3] and humans (42%).^[4] They are only present in eukaryotes but share features with retroviruses such as HIV, for example, discontinuous reverse transcriptase-mediated extrachromosomal recombination.^[5]^[6]

There are two main types of retrotransposons, long terminal repeats (LTRs) and non-long terminal repeats (non-LTRs). Retrotransposons are classified based on sequence and method of transposition.^[7] Most retrotransposons in the maize genome are LTR, whereas in humans they are mostly non-LTR.

^ Dombroski BA, Feng Q, Mathias SL, Sassaman DM, Scott AF, Kazazian HH, Boeke JD (July 1994). "An in vivo assay for the reverse transcriptase of human retrotransposon L1 in Saccharomyces cerevisiae". Molecular and Cellular Biology. 14 (7): 4485–92. doi:10.1128/mcb.14.7.4485. PMC 358820. PMID 7516468.
^ Craig, Nancy Lynn (2015). Mobile DNA III. Washington (D.C.): ASM press. ISBN 9781555819200.
^ SanMiguel P, Bennetzen JL (1998). "Evidence that a recent increase in maize genome size was caused by the massive amplification of intergene retrotranposons". Annals of Botany. 82 (Suppl A): 37–44. doi:10.1006/anbo.1998.0746.
^ Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, Baldwin J, et al. (February 2001). "Initial sequencing and analysis of the human genome". Nature. 409 (6822): 860–921. Bibcode:2001Natur.409..860L. doi:10.1038/35057062. hdl:2027.42/62798. PMID 11237011.
^ Sanchez DH, Gaubert H, Drost HG, Zabet NR, Paszkowski J (November 2017). "High-frequency recombination between members of an LTR retrotransposon family during transposition bursts". Nature Communications. 8 (1): 1283. Bibcode:2017NatCo...8.1283S. doi:10.1038/s41467-017-01374-x. PMC 5668417. PMID 29097664.
^ Drost HG, Sanchez DH (December 2019). "Becoming a Selfish Clan: Recombination Associated to Reverse-Transcription in LTR Retrotransposons". Genome Biology and Evolution. 11 (12): 3382–3392. doi:10.1093/gbe/evz255. PMC 6894440. PMID 31755923.
^ Xiong Y, Eickbush TH (October 1990). "Origin and evolution of retroelements based upon their reverse transcriptase sequences". The EMBO Journal. 9 (10): 3353–62. doi:10.1002/j.1460-2075.1990.tb07536.x. PMC 552073. PMID 1698615.

[1] Dombroski BA, Feng Q, Mathias SL, Sassaman DM, Scott AF, Kazazian HH, Boeke JD (July 1994). "An in vivo assay for the reverse transcriptase of human retrotransposon L1 in Saccharomyces cerevisiae". Molecular and Cellular Biology. 14 (7): 4485–92. doi:10.1128/mcb.14.7.4485. PMC 358820. PMID 7516468.

[2] Craig, Nancy Lynn (2015). Mobile DNA III. Washington (D.C.): ASM press. ISBN 9781555819200.

[SanMiguelandBennetzen-3] SanMiguel P, Bennetzen JL (1998). "Evidence that a recent increase in maize genome size was caused by the massive amplification of intergene retrotranposons". Annals of Botany. 82 (Suppl A): 37–44. doi:10.1006/anbo.1998.0746.

[Landeretal-4] Lander ES, Linton LM, Birren B, Nusbaum C, Zody MC, Baldwin J, et al. (February 2001). "Initial sequencing and analysis of the human genome". Nature. 409 (6822): 860–921. Bibcode:2001Natur.409..860L. doi:10.1038/35057062. hdl:2027.42/62798. PMID 11237011.

[5] Sanchez DH, Gaubert H, Drost HG, Zabet NR, Paszkowski J (November 2017). "High-frequency recombination between members of an LTR retrotransposon family during transposition bursts". Nature Communications. 8 (1): 1283. Bibcode:2017NatCo...8.1283S. doi:10.1038/s41467-017-01374-x. PMC 5668417. PMID 29097664.

[6] Drost HG, Sanchez DH (December 2019). "Becoming a Selfish Clan: Recombination Associated to Reverse-Transcription in LTR Retrotransposons". Genome Biology and Evolution. 11 (12): 3382–3392. doi:10.1093/gbe/evz255. PMC 6894440. PMID 31755923.

[7] Xiong Y, Eickbush TH (October 1990). "Origin and evolution of retroelements based upon their reverse transcriptase sequences". The EMBO Journal. 9 (10): 3353–62. doi:10.1002/j.1460-2075.1990.tb07536.x. PMC 552073. PMID 1698615.

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