Elsevier

Developmental Biology

Volume 269, Issue 1, 1 May 2004, Pages 276-285
Developmental Biology

RNAi and expression of retrotransposons MuERV-L and IAP in preimplantation mouse embryos

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Abstract

Both murine endogenous retrovirus-L (MuERV-L) and intracisternal A particle (IAP), two autonomous long terminal repeat (LTR) retrotransposons, are activated during genome activation in the preimplantation mouse embryo, and both sense and antisense transcripts are detected in 2-cell and 8-cell stage embryos. Because RNA interference (RNAi) functions in the preimplantation mouse embryo, we analyzed the relationship between RNAi and MuERV-L and IAP expression by inhibiting RNAi and measuring relative changes of the levels of these transcripts. We inhibited the initial step in the RNAi pathway by injecting 1-cell embryos with mDicer siRNA or long mDicer dsRNA and analyzed MuERV-L and IAP expression at the 8-cell stage. This approach resulted in the targeted destruction of mDicer mRNA, but not Hdac1 mRNA, inhibited the RNAi pathway, and resulted in a 50% increase in IAP and MuERV-L transcript abundance. These results suggest that RNAi constrains expression of repetitive parasitic sequences in preimplantation embryos, and thereby contributes to preserving genomic integrity at a stage of development when the organism consists of only a few cells.

Keywords

RNAi
Retrotransposon
Dicer
Preimplantation embryo
Genome activation

Cited by (0)

1

These authors contributed equally to this work.

2

Current address: Friedrich Miescher Institute for Biomedical Research, PO Box 2543, 4002 Basel, Switzerland.