A novel tripartite structure comprising a mariner-like element and two additional retrotransposons found in the Bombyx mori genome

Yumiko Nakajima, Kazuo Hashido, Kozo Tsuchida, Naoko Takada, Teiichiro Shiino, Hideaki Maekawa

Research output: Contribution to journalArticle

10 Citations (Scopus)


A clone of a DNA-mediated mobile element (transposon) corresponding to a mariner-like element (MLE) was obtained by carrying out the polymerase chain reaction with genomic DNA of Bombyx mori using a Hyalophora cecropia MLE sequence as a primer. This clone had a size of about 4.2 kb and, after sequencing, was found to contain an RNA-mediated, shorter retrotransposon named L1Bm, which was in turn integrated with a much longer retrotransposon named BMC1. Thus, the mobile elements made a novel tripartite structure. The BMC1 and L1Bm moieties of the composite structure each contained a 63-bp conserved sequence which was subsequently found to be highly conserved in all BMC1 and L1Bm elements registered so far. We propose that the 63-bp stretch may be a recognition site for a retrotransposition mechanism conducted by a reverse transcriptase and an endonuclease complex. On the basis of this inference, we propose a model that predicts how different types of BMC1 and L1Bm elements are dispersed in the genome. In addition, a phylogenetic tree made from the current and extant BMC1 and L1Bm sequences indicated that these elements can be classified into Subfamilies I and II.

Original languageEnglish
Pages (from-to)577-585
Number of pages9
JournalJournal of Molecular Evolution
Issue number5
Publication statusPublished - Jan 1 1999
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics

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