tRNAs as primer of reverse transcriptases
Genetic elements coding for proteins that present amino acid identity with the conserved motifs of retroviral reverse transcriptases constitute the retroid family. With the exception of reverse transcriptases encoded by mitochondrial plasmids of Neurospora, all reverse transcriptases have an absolut...
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Published in | Biochimie Vol. 77; no. 1; pp. 113 - 124 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
France
Elsevier Masson SAS
1995
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Subjects | |
Online Access | Get full text |
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Summary: | Genetic elements coding for proteins that present amino acid identity with the conserved motifs of retroviral reverse transcriptases constitute the retroid family. With the exception of reverse transcriptases encoded by mitochondrial plasmids of
Neurospora, all reverse transcriptases have an absolute requirement for a primer to initiate DNA synthesis. In retroviruses, plant pararetroviruses, and retrotransposons (transposons containing long terminal repeats), DNA synthesis is primed by specific tRNAs. All these retroelements contain a primer binding site presenting a Watson-Crick complementarity with the primer tRNA. The tRNAs most widely used as primers are tRNA
Tm, tRNA
Pro, tRNA
1,2
Lys, tRNA
3
Lys, tRNA
1
Met. Other tRNAs such as tRNA
Gln,tRNA
Leu, tRNA
Ser, tRNA
Asn and tRNA
Arg are also occasionally used as primers. In the retroviruses and plant pararetroviruses, the primer binding site is complementary to the 3′ end of the primer tRNA. In the case of retrotransposons, the primer binding site is either complementary to the 3′ end or to an internal region of the primer tRNA. Additional interactions taking place between the primer tRNA and the retro-RNA outside of the primer binding site have been evidenced in the case of Rous sarcoma virus, human immunodeficiency virus type I, and yeast retrotransposon Ty1. A selective encapsidation of the primer tRNA, probably promoted by interactions with reverse transcriptase, occurs during the formation of virus or virus-like particles. Annealing of the primer tRNA to the primer binding site appears to be mediated by reverse transcriptase and/or the nucleocapsid protein. Modified nucleosides of the primer tRNA have been shown to be important for replication of the primer binding site, encapsidaion of the primer (in the case of Rous sarcoma virus), and interaction with the genomic RNA (in the case of human immunodeficiency virus type I). |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 ObjectType-Article-2 ObjectType-Feature-3 ObjectType-Review-1 |
ISSN: | 0300-9084 1638-6183 |
DOI: | 10.1016/0300-9084(96)88114-4 |