Reverse transcriptase encoded by a retrotransposon from the trypanosomatid Crithidia fasciculata

Abram Gabriel, Jef D. Boeke

Research output: Contribution to journalArticlepeer-review


The long interspersed nuclear element (LINE)-like elements are a distinct family of eukaryotic transposons that contain a long open reading frame with limited sequence homology to retroviral reverse transcriptases. Unlike many retrotransposons, they lack long terminal repeats. The mechanism by which LINE-like elements move within the genomes of their hosts remains speculative. We have used an unusual approach to express and detect enzymatic activities associated with Crithidia retrotransposable element 1(CRE1), a site-specific LINE-like element found in the insect trypanosomatid Crithidia fasciculata. A chimeric gene fusing the yeast retrotransposon Ty1 and the CRE1 open reading frame is constructed and then overexpressed in yeast. Fusion proteins are packaged into virus-like particles, which can be partially purified and directly analyzed for enzymatic activity. Here we demonstrate that CRE1 encodes an RNA-directed DNA polymerase. These data provide direct biochemical evidence that this widely distributed class of retrotransposons encodes reverse transcriptase and sets the stage for a detailed understanding of the mechanisms involved in LINE-like element transposition.

Original languageEnglish (US)
Pages (from-to)9794-9798
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number21
StatePublished - 1991

ASJC Scopus subject areas

  • General


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