Sequence-nonspecific suppression of gene expression by double-stranded RNA in silkworm cultured cells

Kosuke Sakashita, Tsuneyuki Tatsuke, Jae Man Lee, Yutaka Kawaguchi, Takahiro Kusakabe

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Double-stranded RNA (dsRNA) induces various biological responses in eukaryotic cells. Sequence-specific RNA interference (RNAi) is highly conserved throughout eukaryotic organisms. In mammalian cells, long dsRNA is known to have sequence-nonspecific gene silencing effect by activating several cellular pathways. As for insect cells, only the smallest amount of information has been reported so far. Here, we investigate the sequence-nonspecific effect of dsRNA on gene expression in a lepidopteran cell line, silkworm Bombyx mori BmN4. Cells were cotransfected with long dsRNA and a reporter plasmid expressing luciferase or β-galactosidase, and measured for the activities of each enzyme. dsRNAs which are not homologous to the target gene reduced the reporter activity in a concentration-dependent manner, albeit its effective concentration was considerably higher than that caused by dsRNA homologous to the target gene. The sequence-nonspecific repression by non-homologous dsRNAs was further confirmed using dsRNAs complementary to several genes from some organisms such as silkworm, fruit fly and human, as well as a synthetic dsRNA, polyinosinic-polycytidylic acid (poly(I:C)). Since the sequence-independent effect by long dsRNA was also observed in another lepidopteran cell line, fall armyworm Spodoptera frugiperda Sf21, it may be one of the conserved immune responses among lepidopteran insects.

Original languageEnglish
Pages (from-to)33-37
Number of pages5
JournalJournal of Insect Biotechnology and Sericology
Issue number1
Publication statusPublished - Feb 2009

All Science Journal Classification (ASJC) codes

  • Applied Microbiology and Biotechnology
  • Insect Science
  • General Business,Management and Accounting
  • General Agricultural and Biological Sciences
  • Biotechnology
  • Industrial and Manufacturing Engineering


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