Analysis of the 5{prime} junctions of R2 insertions with the 28S gene: Implications for non-LTR retrotransposition

Journal Article · Fri Mar 01 00:00:00 EST 1996 · Genetics

OSTI ID:539427

George, J A; Burke, W D; Eickbush, T H ^[1]

---

1. Univ. of Rochester, NY (United States)

R2 elements are non-long terminal repeat retrotransposable elements that insert into 28S rRNA genes of most insect species. The single open reading frame of R2 encodes a protein with both endonuclease activity, which cleaves the target site, and reverse transcriptase activity, which uses this cleavage to prime reverse transcription. This target-primed reverse transcription mechanism is also used by group II introns. Little is known of the mechanism by which the 5{prime} end of R2 is integrated after reverse transcription. We have determined the 5{prime} junction sequence of 94 R2 elements from 14 different species of Drosophila. Only 37% of the full-length elements contained precise 5{prime} junctions; the remainder contained deletions of the 28S gene and/or insertions of additional sequences. Because the 5{prime} junctions of truncated copies were similar to full-length elements, no sequences at the 5{prime} end of R2 appear to be required for element integration. A model in which the R2 reverse transcriptase is capable of switching templates from the R2 RNA transcript to the upstream 28S gene can best explain the observed 5{prime} junction sequences. This template jumping is analogous to the template switching of retroviral reverse transcriptases during formation of the double-stranded integration products. 44 refs., 5 figs.

• OSTI ID: 539427
• Journal Information: Genetics, Vol. 142, Issue 3; Other Information: PBD: Mar 1996
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
DROSOPHILA
STRAINS
GENES
TRANSCRIPTION
STRUCTURE-ACTIVITY RELATIONSHIPS
DNA SEQUENCING
GENE MUTATIONS
GENETIC MAPPING
GENE RECOMBINATION
FUNCTIONAL MODELS
BIOLOGICAL MODELS
ENDONUCLEASES
ENZYME ACTIVITY
DNA
DNA REPAIR
BIOSYNTHESIS
INTRONS
RNA
INSECTS
POLYMERASE CHAIN REACTION
AMINO ACID SEQUENCE