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Centromere-targeted de novo integration of an LTR retrotransposon of Arabidopsis lyrata
Genes & Development
Division of Agricultural Genetics , Kakutani Group

Centromere-targeted de novo integrations of an LTR retrotransposon of Arabidopsis lyrata.
Tsukahara, S., Kawabe,A., Kobayashi, A., Ito, T., Aizu, T., Shin-i, T., Toyoda, A., Fujiyama, A., Tarutani, Y., and Kakutani, T.
Genes Dev, 26, 705-713. doi: 10.1101/gad.183871.111  

In many eukaryotes including vertebrates, insects and plants, centromeres have high proportion of repeats and transposons, which contribute to heterochromatin formation, cohesion, and chromosomal segregation (Fig 1). The high proportion of transposons in the centromeres suggests targeted integration of these transposons. Paradoxically, however, no transposon targeting to centromere is known. Here, using a flowering plant Arabidopsis, we report such targeted transposon integrations de novo. By combination of genetics and genomics, we show that a mobile LTR retrotransposon, named Tal1 (transposon of Arabidopsis lyrata 1), integrates almost exclusively into centromeres (Fig 2). We identified hundreds of new and specific Tal1 integrations into centromeres. This provides a direct way to investigate impact of transposon accumulation in centromeres, which address central issues of molecular mechanisms controlling genome evolution. Furthermore, mobility of Tal1 and related elements revealed unexpectedly dynamic control for evolution of the repeats.

Figure1

As in many organisms, repetitive sequences accumulate around centromeres of Arabidopsis and form condensed structure.

Figure1

Tal1  (Transposon in A. lyrata 1) was  introduced into A. thaliana by transformation. Tal1 was retrotransposed and integrated almost exclusively into centromeric repeats in A. thaliana.


Genes & Development, PERSPECTIVE