title: A serpin from Chinese shrimp Fenneropenaeus chinensis is responsive to bacteria and WSSV challenge.
abstract: Arthropod defence responses (e.g. prophenoloxidase (proPO) activation and Toll pathway initiation) are mediated by serine proteinase cascades and regulated by serpins in haemolymph. A serpin (Fc-serpin) cDNA was cloned from the haemocytes of Fenneropenaeus chinensis by rapid amplification of cDNA ends (RACE) PCR and haemocyte cDNA library screening. The full-length cDNA consists of 1734bp, encoding 411 amino acids with a calculated molecular mass of 46.55kDa and a theoretical isoelectric point of 7.70. Fc-serpin contains a typical serpin-like homologue (serine proteinase inhibitors domain). The deduced protein contains a putative signal peptide of 19 amino acids and the serpin's signature sequence ((379)FHCNRPFLFLI(389)). Fc-serpin showed some identity with Pacifastacus leniusculus serpin (42%) and Manduca sexta serpin-6 (34%). The reactive centre loop (RCL) sequences of Fc-serpin, P. leniusculus serpin, M. sexta serpin-6 and Bombyx mori serpin-2 are highly similar. An Arg at the P1 position of the reactive site indicates that Fc-serpin may have inhibitory activity against prophenoloxidase activating proteinase (PAP) and clotting enzyme. Transcripts of Fc-serpin mRNA were mainly detected in haemocytes and the lymphoid organ by RT-PCR. The variation of the mRNA transcription level in haemocytes followed by artificial infection with bacteria or white spot syndrome virus (WSSV) was quantified by SYBR Green real-time PCR analysis. Expression profiles of Fc-serpin greatly fluctuated after challenge. This work represents the first report of a serpin in penaeid shrimp. The data provide clues that Fc-serpin might play potential roles in the innate immunity of shrimp.
authors.affiliation: College of Chemistry and Life Science, Tianjin Normal University, Tianjin 300387, China.
authors.forename: Yichen
authors.initials: Y
authors.lastname: Liu
authors.forename: Fuhua
authors.initials: F
authors.lastname: Li
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Dong
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhang
authors.forename: Jianhai
authors.initials: J
authors.lastname: Xiang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020869:Gene Expression Profiling; D008958:Models, Molecular; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000821:virology; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D015843:Serpins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000502:physiology*; D013997:Time Factors; D014733:Vibrio / Q000502:physiology*; D046848:White spot syndrome virus 1 / Q000502:physiology*
chemical_list: D012333:RNA, Messenger; D015843:Serpins