title: The Rab1 GTPase of Sciaenops ocellatus modulates intracellular bacterial infection.
abstract: The Rab family proteins belong to the Ras-like GTPase superfamily and play important roles in intracellular membrane trafficking. To date no studies on fish Rab have been documented, though rab-like sequences have been found in a number of teleosts. In this study, we identified and analyzed a Rab homologue, SoRab1, from red drum, Sciaenops ocellatus. The cDNA of SoRab1 contains a 5'- untranslated region (UTR) of 358 bp, an open reading frame (ORF) of 612 bp, and a 3'-UTR of 265 bp. The ORF encodes a putative protein of 203 residues, which shares 92-99% overall sequence identities with the Rab1 from fish, human, and mouse. SoRab1 possesses a typical Rab1 GTPase domain with the conserved G box motifs and the switch I and switch II regions. Recombinant SoRab1 purified from Escherichia coli exhibits apparent GTPase activity. Quantitative real time RT-PCR analysis showed that SoRab1 expression was detected in a number of tissues, with the lowest expression found in blood and highest expression found in muscle. Bacterial and lipopolysaccharide challenges significantly upregulated SoRab1 expression in liver, kidney, and spleen in time-dependent manners. Transient overexpression of SoRab1 in primary hepatocytes reduced intracellular bacterial infection, whereas interference with SoRab1 expression by RNAi enhanced intracellular bacterial invasion. These results provide the first indication that a fish Rab1 GTPase, SoRab1, regulates intracellular bacterial infection and thus is likely to play a role in bacteria-induced host immune defense.
authors: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China.
authors: Yong-hua
authors: YH
authors: Hu
authors: Tian
authors: T
authors: Deng
authors: Li
authors: L
authors: Sun
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001424:Bacterial Infections / Q000276:immunology / Q000378:metabolism / Q000662:veterinary*; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli; D005393:Fish Diseases / Q000276:immunology* / Q000378:metabolism*; D040461:Gene Components; D020869:Gene Expression Profiling / Q000662:veterinary; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000276:immunology; D015151:Immunoblotting / Q000662:veterinary; D042541:Intracellular Space / Q000382:microbiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010473:Perciformes; D010957:Plasmids / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D017385:Sequence Homology; D013045:Species Specificity; D020761:rab1 GTP-Binding Proteins / Q000276:immunology* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D008070:Lipopolysaccharides; D020761:rab1 GTP-Binding Proteins