The Caenorhabditis elegans Argonautes ALG-1 and ALG-2: Almost Identical yet Different

Abstract

Since the discovery of the RNA interference pathway, several other small RNA pathways have been identified. These makeuse of the same basic machinery to generate small RNA molecules that can direct different types of (post)transcriptionalsilencing. The specificity for the different silencing pathways (which type of silencing a small RNA initiates) is likely accomplishedby the effector molecules that bind the small RNAs: the Argonaute proteins. Two Argonaute proteins, ALG-1 andALG-2, have been implicated in one of the silencing pathways, the microRNA (miRNA) pathway, in Caenorhabditis elegans.The two proteins are highly similar, and previous work suggested redundancy of the two proteins. Here, we present geneticand biochemical data that hint at individual nonredundant functions for ALG-1 and ALG-2 in the processing of precursormiRNAs to mature miRNAs.