BACKGROUND: Transposable elements (TEs) are common constituents of centromeres. However, it is not known what causes this relationship. @entity25908 contains 10 families of Long Terminal Repeat (LTR)-retrotransposons and these elements cluster in centromeres and telomeres. In the related @entity375 , @entity6739 LTR-retrotransposons Tf1 and Tf2 are distributed in the promoter regions of RNA pol II transcribed genes. Sequence analysis of TEs indicates that Tj1 of @entity25908 is related to Tf1 and Tf2, and uses the same mechanism of self-primed reverse transcription. Thus, we wondered why these related retrotransposons localized in different regions of the genome. RESULTS: To characterize the integration behavior of Tj1 we expressed it in @entity6739 . We found Tj1 was active and capable of generating de novo integration in the chromosomes of @entity6739 . The expression of Tj1 is similar to Type C retroviruses in that a stop codon at the end of Gag must be present for efficient integration. 17 inserts were sequenced, 13 occurred within 12  bp upstream of tRNA genes and 3 occurred at other RNA pol III transcribed genes. The link between Tj1 integration and RNA pol III transcription is reminiscent of Ty3, an LTR-retrotransposon of @entity375 that interacts with TFIIIB and integrates upstream of tRNA genes. CONCLUSION: The integration of Tj1 upstream of tRNA genes and the centromeric clustering of tRNA genes in @entity25908 demonstrate that the clustering of this TE in centromere sequences is due to a unique pattern of integration.

A long terminal repeat retrotransposon of XXXX integrates upstream of RNA pol III transcribed genes.

@entity6739 :: ('4896', 'Species') :: ['Schizosaccharomyces pombe', 'S. pombe'] @entity375 :: ('4932', 'Species') :: ['yeast', 'Saccharomyces cerevisiae'] @entity25908 :: ('4897', 'Species') :: ['S. japonicus', 'Schizosaccharomyces japonicus']
@entity25908 :: (4897,Species) :: ['Schizosaccharomyces japonicus']
