Argonaute-like proteins in protists. A. Schematic representation of Argonaute-like proteins. TbAGO1, Trypanosoma brucei AGO1 (accession number AY433802); TbPWI1, Trypanosoma brucei PWI1 (AY433803); LmPWI1, Leishmania major AGO1 (AL446005); GlAGO1, Giardia intestinalis AGO1 (AY142143); SpAGO1 Schizosaccharomyces pombe AGO1 (CAA19275); TtTWI1 Tetrahymena thermophila TWI1 (AB084111); AtAGO1, Arabidopsis thaliana AGO1 (U91995), CeRDE1, Caenorhabditis elegans RDE1 (AF180730); NcQDE2, Neurospora crassa QDE2 (AF217760); DmAGO2, Drosophila melanogaster AGO2 (NM168626). The red and yellow boxes indicate PAZ and Piwi domains respectively. The TbAGO1 RGG box is shown in green, the DmAGO2 poly-Q box is shown in blue and the N-terminal extension of AtAGO1 is annotated as a poly-Q box but also containing RGG motives and is shown in blue and green. B. Amino-terminal extensions of TbAGO1 and AtAGO1 contain RGG boxes. The RGG motifs are shown in red and the poly-Q box in blue. C. TbAGO1 and TbPWI1 RNA are expressed in the culture-adapted procyclic stage of T. brucei. Total RNA extracted from wild-type trypanosomes was incubated with (+) or without (-) reverse transcriptase and PCR-amplified using specific primers for the indicated genes.