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Volume 15, Issue 1 (Mar 2010)

The telomere-specific non-LTR retrotransposons SART1 and TRAS1 are suppressed by Piwi subfamily proteins in the silkworm, Bombyx mori

Tsuneyuki Tatsuke
  • Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
  • Research Fellow of the Japan Society for the Promotion of Science, Fukuoka, Japan
  • Email:
/ Kosuke Sakashita
  • Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
  • Email:
/ Yuki Masaki
  • Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
  • Email:
/ Jae Lee
  • Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
  • Email:
/ Yutaka Kawaguchi
  • Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
  • Email:
/ Takahiro Kusakabe
  • Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, Hakozaki 6-10-1, Fukuoka, 812-8581, Japan
  • Email:
Published Online: 2009-12-21 | DOI: https://doi.org/10.2478/s11658-009-0038-9


The telomere structures in Bombyx mori are thought to be maintained mainly by the transposition of the specialized telomeric retroelements SART and TRAS. The silkworm genome has telomeric TTAGG repeats and telomerase, but this telomerase displays little or no activity. Here, we report that the transcription of the telomeric retroelements SART1 and TRAS1 is suppressed by the silkworm Piwi subfamily proteins BmAgo3 and Siwi. The silkworm Piwi subfamily was found to be expressed predominantly in the gonads and early embryo, as in other model organisms, but in BmN4 cultured cells, these proteins formed granules that were separate from the nuage, which is a different behaviour pattern. The expression of TRAS1 was increased in BmN4 cells when BmAgo3 or Siwi were silenced by RNAi. Our results suggest that B. mori Piwi proteins are involved in regulating the transposition of telomeric retroelements, and that the functional piRNA pathway is conserved in BmN4 cultured cells.

Keywords: Bombyx mori; SART1; TRAS1; Telomere; Piwi

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About the article

Published Online: 2009-12-21

Published in Print: 2010-03-01

Citation Information: Cellular and Molecular Biology Letters, ISSN (Online) 1689-1392, DOI: https://doi.org/10.2478/s11658-009-0038-9. Export Citation

© 2009 University of Wrocław, Poland. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. (CC BY-NC-ND 3.0)

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