RNA Pol IV Plays Catch with Argonaute 4

Small-interfering RNAs regulate gene expression by affecting chromatin structure, transcription, translation, and RNA stability. In a recent report in Genes & Development, El-Shami et al. (2007) show that in plants, Argonaute 4—which is involved in RNA-directed DNA methylation—directly associates with RNA polymerase IVb through a repeat motif, establishing an intimate molecular link between RNAi and transcription