Transgene and transposon silencing in Chlamydomonas reinhardtii by a DEAH-Box RNA helicase

The molecular mechanism(s) responsible for posttranscriptional gene silenci ng and RNA interference remain poorly understood. We have cloned a gene (Mu t6) from the unicellular green alga Chlamydomonas reinhardtii that is requi red for the silencing of a transgene and two transposon families, Mut6 enco des a protein that is highly homologous to RNA helicases of the DEAH-box fa mily, This protein is necessary for the degradation of certain aberrant RNA s, such as improperly processed transcripts, which are often produced by tr ansposons and some transgenes.