title: Multifunctional murrel caspase 1, 2, 3, 8 and 9: Conservation, uniqueness and their pathogen-induced expression pattern.
abstract: Caspases are evolutionarily conserved proteases which play fundamental role in apoptosis. Invasion of pathogen triggers the activation of caspases-mediated pro-inflammatory and pro-apoptotic pathways, where multifunctional caspases are involved. In striped murrel Channa striatus, epizootic ulcerative syndrome (EUS) causes endemics resulting in huge economic loss. Aphanomyces invadans, an oomycete is the primary causative agent of EUS which further induces secondary bacterial infections especially Aeromonas hydrophila. In order to get insights into the caspase gene family in C. striatus during EUS infection, we performed various physicochemical and structural analyses on the cDNA and protein sequences of five different murrel caspases namely CsCasp 1, 2, 3, 8 and 9. Sequence analysis of murrel caspase proteins showed that in spite of the conserved CASC domain, each caspase embraces some unique features which made them functionally different. Tissue distribution analysis showed that all the murrel caspases are highly expressed in one of the immune organs such as liver, kidney, spleen and blood cells. Further, to understand the role of caspase during EUS infection, modulation in expression of each caspase gene was analysed after inducing fungal and bacterial infection in C. striatus. Pathogen-induced gene expression pattern revealed an interesting fact that the expression of all the caspase genes reached a maximum level at 24 h post-infection (p.i) in case of bacteria, whereas it was 48 h in fungus. However, the initiation of elevated expression differed between each caspase based on their role such as pro-inflammatory, initiator and executioner caspase. Overall, the results suggested that the caspases in murrel are diverse in their structure and function. Here, we discuss the similarities and differences of five different murrel caspases.
authors.affiliation: Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Kumaresan
authors.affiliation: Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India; SRM Research Institute, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
authors.forename: Gayathri
authors.initials: G
authors.lastname: Ravichandran
authors.affiliation: Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India.
authors.forename: Faizal
authors.initials: F
authors.lastname: Nizam
authors.affiliation: Centre for Biotechnology, Anna University, Chennai, 600 025, Tamil Nadu, India.
authors.forename: Nagarajan Balachandran
authors.initials: NB
authors.lastname: Dhayanithi
authors.affiliation: Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh, 11451, Saudi Arabia.
authors.forename: Mariadhas Valan
authors.initials: MV
authors.lastname: Arasu
authors.affiliation: Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh, 11451, Saudi Arabia.
authors.forename: Naif Abdullah
authors.initials: NA
authors.lastname: Al-Dhabi
authors.affiliation: Department of Zoology, Pachaiyappa's College for Men, Kanchipuram, 631 501, Tamil Nadu, India.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Harikrishnan
authors.affiliation: Division of Fisheries Biotechnology & Molecular Biology, Department of Biotechnology, Faculty of Science and Humanities, SRM University, Kattankulathur, 603 203, Chennai, Tamil Nadu, India. Electronic address: jesuaraj@hotmail.com.
authors.forename: Jesu
authors.initials: J
authors.lastname: Arockiaraj
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D044744:Aphanomyces / Q000502:physiology; D020169:Caspases / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005393:Fish Diseases / Q000276:immunology*; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000662:veterinary*; D010473:Perciformes / Q000145:classification / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D020169:Caspases
keywords: Caspase; Epizootic ulcerative syndrome; Innate immunity; Pathogen-induced gene expression; Snakehead murrel