title: Isolation and characterization of cDNA encoding Argonaute, a component of RNA silencing in shrimp (Penaeus monodon).
abstract: We have identified a cDNA clone that encodes a protein with high sequence homology to Argonaute proteins of mammals and Drosophila melanogaster. The cDNA of Penaeus monodon (Pm Ago) consisted of 3178 nucleotides encoding 939-amino acid residues with a calculated molecular weight of 104 kDa. The primary structure of Pm Ago showed the presence of two signature domains, PAZ and PIWI domains that exhibit highest homology to their counterparts in D. melanogaster. The inferred protein sequence of Pm Ago was 80.8% identical with D. melanogaster and 82.1% identical with Anopheles gambiae Ago proteins. Phylogenetic analysis of Pm Ago with other invertebrate and vertebrate Argonaute proteins suggested that Pm Ago belongs to the Ago1 subfamily that plays crucial roles in stem cell differentiation or RNA interference (RNAi). Semi-quantitative RT-PCR analysis showed that the gene is highly expressed in the lymphoid organ and moderately expressed in intestine, muscle, pleopods and hemocytes. The expression of Pm Ago1 mRNA was 2-3-fold increased during the early period of viral infection but declined rapidly at 30 hour post infection. By contrast, infection of shrimp by a bacterial pathogen, Vibrio harveyi did not induce a reduction of Pm Ago1 mRNA suggesting that its expression is associated with virus infection.
authors.affiliation: Center of Excellence for Shrimp Biotechnology, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Sasimanas
authors.initials: S
authors.lastname: Unajak
authors.forename: Vichai
authors.initials: V
authors.lastname: Boonsaeng
authors.forename: Sarawut
authors.initials: S
authors.lastname: Jitrapakdee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D034622:RNA Interference; D012327:RNA Virus Infections / Q000378:metabolism; D034743:RNA-Induced Silencing Complex / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D034743:RNA-Induced Silencing Complex