What is retrotransposon?

Felipe N. Soto F-Soto at uiuc.edu
Thu Jul 20 09:59:15 EST 1995


> Naresh a retroposon is a type of "mobile DNA element" that moves (translocates) via
> an RNA intermediate from which it is reverse transcribed and then the DNA copy integrates ectopically
> somewhere in the genome.  But these are not retroviral like in that they lack, in general, any IR or LTR's
> at there termini 

I think we might be getting bogged down in some unfortunate terminology
here. Retroposon is kind of confusing and doesn't describe the true
diversity of these mobile elements.  The current term favored for the
entire class of elements that encode reverse transcriptase is
retroelements.  There are large subdivisions within that grouping.  These
include the retroviruses, which are infectious; the   LTR retrotransposons
which resemble retroviruses in that they contain long terminal repeats of
up to several hundred base pairs, code for gag-like proteins and integrase
but are apparently uninfective; the Non-LTR retrotransposons described by
Graham Dellaire in a previous response that don't encode integrase and have
no LTRs; and the pararetroviruses like Cauliflower mosaic virus.  Probably
the best review of this entire subject area, including the DNA mediated
elements, is the book edited by Berg and Howe, "Mobile DNA".  All kinds of
information in there on a wide variety of RNA mediated elements.  Another
excellent review is Thomas Eickbush's "Origin and Evolutionary
Relationships of Retroelements" in the recently published The Evolutionary
Biology of Viruses edited by S.S. Morse.

David Lampe
Dept. Entomology
University of Illinois
505 S. Goodwin
Urbana, Illinois  61801  USA  
d-lampe at uiuc.edu   
1980 BMW R100T
"No hour spent in the saddle is wasted" -Winston Churchill

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