We know Jason and the Argonauts who retrieved the Golden Fleece and fought hydra, cyclop and all those monsters. But, this is about another kind of Argonaute, which is a key protein in RNA silencing.Similar to Argonauts fighting monsters, the Argonaute protein can help protect against viruses in arthropods including shrimp by destroying viral RNA by RNA silencing mechanism. Not only viruses, Argonautes also provide protection against transposon, a mobile genetic element. A recent finding from Dr. Apinunt Udomkit showed that a new member of Argonutes in the black tiger shrimp called Argonaute 4 (PmAgo4) is potentially a key protein in the repression of transposons. The silencing of PmAgo4 led to the activation of several types of transposons in shrimp testis. Because jumping of transposons to a new site in the genome could disrupt genome structure and gene function, PmAgo4 may serve as a guardian of shrimp genome, particularly in the germline cells, from the invasion of transposons in this regards. Leebonoi W(1), Sukthaworn S(1), Panyim S(2), Udomkit A(3). A novel gonad-specific Argonaute 4 serves as a defense against transposons in the black tiger shrimp Penaeus monodon. Fish Shellfish Immunol. 2015 Feb;42(2):280-8.