Convergent evolution of ribonuclease h in LTR retrotransposons and retroviruses.

Abstract

Ty3/Gypsy long terminals repeat (LTR) retrotransposons are structurally and phylogenetically close to retroviruses. Two notable structural differences between these groups of genetic elements are 1) the presence in retroviruses of an additional envelope gene, env, which mediates infection, and 2) a specific dual ribonuclease H (RNH) domain encoded by the retroviral pol gene. However, similar to retroviruses, many Ty3/Gypsy LTR retrotransposons harbor additional env-like genes, promoting concepts of the infective mode of these retrotransposons. Here, we provide a further line of evidence of similarity between retroviruses and some Ty3/Gypsy LTR retrotransposons. We identify that, together with their additional genes, plant Ty3/Gypsy LTR retrotransposons of the Tat group have a second RNH, as do retroviruses. Most importantly, we show that the resulting dual RNHs of Tat LTR retrotransposons and retroviruses emerged independently, providing strong evidence for their convergent evolution. The convergent resemblance of Tat LTR retrotransposons and retroviruses may indicate similar selection pressures acting on these diverse groups of elements and reveal potential evolutionary constraints on their structure. We speculate that dual RNH is required to accelerate retrotransposon evolution through increased rates of strand transfer events and subsequent recombination events.

• Authors: Kirill Ustyantsev, Olga Novikova, Alexander Blinov, Georgy Smyshlyaev
• Journal: Molecular biology and evolution (Mol Biol Evol) Vol. 32 Issue 5 Pg. 1197-207 (May 2015) ISSN: 1537-1719 [Electronic] United States
• PMID: 25605791 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Chemical References

• Retroelements
• Ribonuclease H

Topics

• Evolution, Molecular
• Phylogeny
• Retroelements (genetics)
• Retroviridae (enzymology, genetics)
• Ribonuclease H (genetics)
• Sequence Alignment
• Terminal Repeat Sequences (genetics)