Fig. 5
From: Conservation and diversification of small RNA pathways within flatworms
Exogenous RNA interference pathway genes detected in flatworms. An exogenous double-stranded RNA is internalized by transmembrane channels SID-1. In the cytoplasm the dsRNA is recognized by RDE4 (an orthologous of R2D2 described in D. melanogaster), this promotes the formation of the DICER complex that process the long dsRNA into 22 nucleotides long dsRNA. The Argonaute protein RDE1 (homologous to Ago2 in D. melanogaster) further process the dsRNA releasing matures siRNA that together with other factors form the effector complex siRISC. mRNAs targeted by siRISC are degraded, XRN1 has 5′-3′ exonuclease activity and intervenes in this process. Mut-7 and RDE-2 act downstream of RDE-1 and RDE-4 and are required for siRNA accumulation. Exogenous RNAi pathway factors with homologous genes detected in flatworms are indicated (“Flatworm Distribution Code” box). A shape code was used to indicate predicted function of factors (“Protein Function Code” box)