Transposons

Abstract

Genomes are highly plastic entities submitted to several types of mutations in somatic and germinal lines. These mutations can alter the general structure of the genome and also its regulation. A large proportion of these events is due to repeated and mobile sequences – the transposable elements.

Keywords: transposon; retrotransposon; retroposon; retroviruses

Figure 1.

Structure of the main classes of transposable elements found in human genome. (a) Class I elements: A and B: RNA polymerase III promoters; Core: conserved region of unknown function; ENDO: endonuclease; gag: capsid gene; pol: polyprotein including reverse transcriptase, integrase, ribonuclease H and protease domains; LTR: long terminal repeat; PBS: primer‐binding site; PTT: polypurine tract; RT: reverse transcriptase; transposase: protein required for the excision and insertion of class II elements. The gray shading for the envelope (env) gene indicates that a functional gene is not always found. (b) Class II elements: ITR: inverted terminal repeat; MITEs: miniature inverted‐repeated transposable elements.

Figure 2.

Structural rearrangements caused by ectopic recombination of TEs. (a) Ectopic recombination involving copies in direct orientation leads to the deletion of the chromosomal portion between the two copies. This mechanism is at the origin of solo‐LTRs, where recombination occurs between the two LTRs of LTR retrotransposons. (b) Ectopic recombination involving copies in inverted orientation leads to the inversion of the chromosomal portion between the two copies.

close

References

Agrawal A, Eastman QM and Schatz DG (1998) Transposition mediated by RAG1 and RAG2 and its implications for the evolution of the immune system. Nature 394: 744–751.

Boeke JD (1997) LINEs and Alus – the polyA connection. Nature Genetics 16: 6–7.

Boeke JD, Eickbush TH, Sandmeyer SB and Voytas OF (1999) Metaviridae. In: Murphy FA (ed.) Virus Taxonomy: ICTV VIIth Report. New York, NY: Springer‐Verlag.

Dawkins R (1976) The Selfish Gene. Oxford, UK: Oxford University Press.

Dawkins R (1982) The Extended Phenotype. Oxford, UK: Oxford University Press.

Deininger PL, Batzer MA, Hutchison III CA and Edgell MH (1992) Master genes in mammalian repetitive DNA amplification. Trends in Genetics 8: 307–311.

Deragon JM and Capy P (2000) Impact of transposable element on the human genome. Annals of Medicine 32: 264–273.

Feschotte C and Mouches C (2000) Evidence that a family of miniature inverted‐repeat transposable elements (MITEs) from the Arabidopsis thaliana genome has arisen from a pogo‐like DNA transposon. Molecular Biology of Evolution 17: 730–737.

Hohjoh H and Singer MF (1997) Ribonuclease and high salt sensitivity of the ribonucleoprotein complex formed by the human LINE‐1 retrotransposon. Journal of Molecular Biology 271: 7–12.

Kipling D and Warburton PE (1997) Centromeres, CENP‐B and Tigger too. Trends in Genetics 13: 141–145.

Lerat E, Brunet F, Bazin C and Capy P (1999) Is the evolution of transposable elements modular? Genetica 107: 15–25.

Malik HS and Eickbush TH (2001) Phylogenetic analysis of ribonuclease H domains suggests a late, chimeric origin of LTR retrotransposable elements and retroviruses. Genome Research 11: 1187–1197.

McClintock B (1984) The significance of responses of the genome to challenge. Science 226: 792–801.

Okada N, Hamada M, Ogiwara I and Ohshima K (1997) SINEs and LINEs share common 3′ sequences: a review. Gene 205: 229–243.

Schmid CW (1998) Does SINE evolution preclude Alu function? Nucleic Acids Research 26: 4541–4550.

Smit AF and Riggs AD (1996) Tiggers and other DNA transposon fossils in the human genome. Proceedings of the National Academy of Sciences of the United States of America 93: 1443–1448.

Whitelaw E and Martin DI (2001) Retrotransposons as epigenetic mediators of phenotypic variation in mammals. Nature Genetics 27: 361–365.

Xiong Y and Eickbush TH (1990) Origin and evolution of retroelements based upon their reverse transcriptase sequences. EMBO Journal 9: 3353–3362.

Further Reading

Capy P, Bazin C, Higuet D and Langin T (1997) Dynamics and Evolution of Transposable elements. Landes Company, Heidelberg, Germany: Springer‐Verlag.

Capy P (1996) Genetica. vol. 100 [Special issue on transposable elements.]

Maraia RJ (1995) The Impact of Short Interspersed Elements (SINEs) on the Host Genome. MBIU, RG Landes Company, Heidelberg, Germany: Springer‐Verlag.

McDonald JF (1992) Genetica 86. [Special issue on transposable elements.]

McDonald JF (1999) Genetica 107. [Special issue on transposable elements.]

Sherrat DJ (1995) Mobile Genetic Elements. Oxford, UK: IRL Press.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Capy, Pierre, and Deragon, Jean‐Marc(Sep 2005) Transposons. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0005064]