Fig. 1.

Domain architecture of core components of the RNAi machinery in green algae. Protein sequences of Chlamydomonas reinhardtii Dicer-like 1 (Cr DCL1) and Argonaute 3 (Cr AGO3), as well as of Coccomyxa sp. strain C-169 RDR (Csp RDR), were examined for the presence of conserved domains by comparison with the SMART and PFAM databases. Polypeptide diagrams are shown to scale. DEAD, DEXD/H-like helicase domain; Heli_C, helicase C-terminal domain; dsRNA-bind, dsRNA binding fold (DUF283); RNase_3a/b, RNase III catalytic domains; PAZ, Piwi-Argonaute-Zwille domain; PIWI, a complex domain consisting of two structural subdomains termed MID and Piwi, the latter resembling an RNase H fold; RdRP, eukaryotic-type RDR domain; aa, amino acids.