Retrotransposon R1Bm endonuclease cleaves the target sequence

Qinghua Feng, Gerald Schumann, Jef D. Boeke

Research output: Contribution to journalArticlepeer-review


The R1Bm element, found in the silkworm Bombyx mori, is a member of a group of widely distributed retrotransposons that lack long terminal repeats. Some of these elements are highly sequence-specific and others, like the human L1 sequence, are less so. The majority of R1Bm elements are associated with ribosomal DNA (rDNA). R1Bm inserts into 28S rDNA at a specific sequence; after insertion it is flanked by a specific 14-bp target site duplication of the 28S rDNA. The basis for this sequence specificity is unknown. We show that R1Bm encodes an enzyme related to the endonuclease found in the human L1 retrotransposon and also to the aparinic/apyrimidinic endonucleases. We expressed and purified the enzyme from bacteria and showed that it cleaves in vitro precisely at the positions in rDNA corresponding to the boundaries of the 14-bp target site duplication. We conclude that the function of the retrotransposon endonucleases is to define and cleave target site DNA.

Original languageEnglish (US)
Pages (from-to)2083-2088
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number5
StatePublished - Mar 3 1998

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Retrotransposon R1Bm endonuclease cleaves the target sequence'. Together they form a unique fingerprint.

Cite this