Role of RNA polymerase III transcription factors in the selection of integration sites by the dictyostelium non-long terminal repeat retrotransposon TRE5-A

Mol Cell Biol. 2006 Nov;26(22):8242-51. doi: 10.1128/MCB.01348-06. Epub 2006 Sep 18.


In the compact Dictyostelium discoideum genome, non-long terminal repeat (non-LTR) retrotransposons known as TREs avoid accidental integration-mediated gene disruption by targeting the vicinity of tRNA genes. In this study we provide the first evidence that proteins of a non-LTR retrotransposon interact with a target-specific transcription factor to direct its integration. We applied an in vivo selection system that allows for the isolation of natural TRE5-A integrations into a known genomic location upstream of tRNA genes. TRE5-A frequently modified the integration site in a way characteristic of other non-LTR retrotransposons by adding nontemplated extra nucleotides and generating small and extended target site deletions. Mutations within the B-box promoter of the targeted tRNA genes interfered with both the in vitro binding of RNA polymerase III transcription factor TFIIIC and the ability of TRE5-A to target these genes. An isolated B box was sufficient to enhance TRE5-A integration in the absence of a surrounding tRNA gene. The RNA polymerase III-transcribed ribosomal 5S gene recruits TFIIIC in a B-box-independent manner, yet it was readily targeted by TRE5-A in our assay. These results suggest a direct role of an RNA polymerase III transcription factor in the targeting process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Dictyostelium / enzymology
  • Dictyostelium / genetics*
  • Gene Expression Regulation, Fungal*
  • Molecular Sequence Data
  • Mutation
  • RNA Polymerase III / genetics*
  • RNA, Transfer / genetics
  • Retroelements / genetics*
  • Sequence Analysis, DNA / methods
  • Terminal Repeat Sequences*
  • Transcription Factors / genetics*
  • Transcription, Genetic


  • Retroelements
  • Transcription Factors
  • RNA, Transfer
  • RNA Polymerase III