Monday, October 06, 2008

Retrotransposons Revisited: The Restraint and Rehabilitation of Parasites

Retrotransposons Revisited: The Restraint and Rehabilitation of Parasites - A review paper appeared in this weeks cell. This paper describes most intricate details about the essence of retrotransposons.

John L. Goodier1, Corresponding Author Contact Information, E-mail The Corresponding Author and Haig H. Kazazian Jr.1
1Department of Genetics, University of Pennsylvania School of Medicine, 415 Curie Boulevard, Philadelphia, PA 19104, USA

Available online 2 October 2008

Here is some excerpts of the paper:

Retroposons mainly the SINES(Short Interspersed Nuclear Elements), LINES(Long Interspersed Nuclear Elements) are endogenous retroviruses, make up roughly 40% of the mammalian genome and have played an important role in genome evolution. In human genome only a small percentage of these LINES(L1s), and SINES are capable of moving into new locations and occasionally causing disease.

There are 2 major groups of such jumping genes. Class II elements or DNA transpososns comprise about 3% of the human genome and most move by a copy paste mechanism. Class I elements comprise of three groups, all moving in a copy paste manner involving reverse transcription of an RNA intermediate and insertion of its cDNA copy or a new site in the genome. Retroviral like or long terminal Reeat(LTR) retrotranspososns include endogenous retroviruses, relics of past rounds of germline infection by viruses that lost their ability to reinfect and become trapped in the genome. These elelments undergo reverse transcription in virus like particles by a complex multistep process. The transposition process for non-LTR retrotransposons is fundamentally different RNA copies of these ellments are likely carried back into the nucleus where their reverse transcription and integration occur in a single step on the DNA itself.

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