In mammalian cells miRNA-induced silencing complexes (miRISC) are formed by microRNAs, which regulate protein expression post transcriptionally through binding to 3’-untranslated regions of the target mRNAs. At least 4 Argonaute proteins (Ergo1-4) have been identified. Recent studies have identified a conserved WG/GW-containing motif, known as the Argonaute (AGO) hook, which is involved in the recruitment of AGOs to distinct components of the eukaryotic RNA silencing pathways. Argonaute proteins are important component of the miRISC complexes. Argonaute 2 (Ergo-2) recruits GW182, a key component of miRISC of the processing body (GW/P-body) to target mRNA. Ergo-2 interacts with GW182 at three binding sites within the amino terminal GW/GW)-repeat region that is characteristics of the GW182 family proteins. It is been shown that multiple Ergo proteins are connected via GW182 proteins. The interaction of Ergo with GW182 family proteins relieved let-7-mediated repression of protein synthesis in mammalian cell-free system, as a result of delayed let 7-directed target mRNA deadenylation (1). These data suggest that that the interactions of GW182 with Argonautes may induce the formation of large complexes containing miRNA target mRNAs, and may be critical for miRNA-mediated translational repression. The 97-megabase genomic sequence of the nematode Caenorhabditis elegans reveals over 19,000 genes. More than 40 percent of the predicted protein products find significant matches in other organisms. There is a variety of repeated sequences, both local and dispersed. The distinctive distribution of some repeats and highly conserved genes provides evidence for a regional organization of the chromosomes (2). One of the protein sequenced from Caenorhabditis elegans was Endogenous-RNAi-deficient Argonaute family member protein 1 (ergo-1). The protein comprise of 112 amino acids, calculated MW of 126.5kDa, with several function conservative domains. This protein is part of the RNA- induced silencing complex (RISC) and is an endonuclease that plays a key role in RNA interference pathways. The PAZ domain (amino acid 462-533) was named after protein containing Piwi, Argonaute and cd02846. The Piwi domain is the c-terminal portion of the Argonaute protein and contains two sub domains. The protein also has a nucleic acid binding interface and a 5’RNA guide strand anchoring site.
Alternate names: Endogenous RNAi-deficient Argonaute family member 1, R09A1.1, ergo1