title: Two types of calmodulin play different roles in Pacific white shrimp (Litopenaeus vannamei) defenses against Vibrio parahaemolyticus and WSSV infection.
abstract: Calmodulin (CaM) plays an important role in calcium-dependent signal transduction pathways. In the present study, two alternative splicing isoforms of CaM (named LvCaM-A and LvCaM-B) cDNA were cloned from the Pacific white shrimp, Litopenaeus vannamei. LvCaM-A was of 1101 bp, including a 5'-terminal untranslated region (UTR) of 70 bp, a 3'-terminal UTR of 581 bp and an open reading frame (ORF) of 450 bp encoding a polypeptide of 149 amino acids with a calculated molecular weight (Mw) of 17 kDa and pI of 4.41. LvCaM-B was 689 bp, including a same 5'-UTR of 70 bp, a 3'-terminal UTR of 109 bp and an ORF of 510 bp encoding a polypeptide of 169 amino acids with a calculated Mw of 19 kDa and pI of 4.36. Both LvCaM-A and LvCaM-B contained 4 conservative EF-hand motifs. Quantitative real-time reverse transcription PCR analysis revealed LvCaM-A to be expressed in most shrimp tissues, with the predominant expression in nerve and the weakest expression in heart. However, LvCaM-B expression level was much weaker than those of LvCaM-A in all the tested tissues with main expression in hepatopancreas. The expression of LvCaM-A and LvCaM-B after challenge with Vibrio parahaemolyticus and WSSV were tested in hemocytes, hepatopancreas and nerve. The results indicated that LvCaM-A and LvCaM-B transcripts could be significantly induced in hemocytes and hepatopancreas respectively by injection with V. parahaemolyticus. The highest expression of LvCaM-A was in the hemocytes with 2.3 times (at 48 h) greater expression than in the control (p < 0.05). However, sharp down-regulation of both LvCaM-A and LvCaM-B were detected in nerve after Vibrio- and WSSV injection (p < 0.05). These results suggested that CaM might play an important role in shrimp's defense against pathogenic infection.
authors.affiliation: Key Laboratory of Science and Technology for Aquaculture and Food Safety of Fujian Province University, Jimei University, Xiamen 361021, China.
authors.forename: Pei-Feng
authors.initials: PF
authors.lastname: Ji
authors.forename: Cui-Luan
authors.initials: CL
authors.lastname: Yao
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002147:Calmodulin / Q000235:genetics* / Q000276:immunology*; D018076:DNA, Complementary; D006434:Hemocytes / Q000276:immunology / Q000382:microbiology / Q000821:virology; D043143:Hepatopancreas / Q000276:immunology / Q000382:microbiology / Q000821:virology; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D014736:Vibrio parahaemolyticus; D046848:White spot syndrome virus 1
chemical_list: D002147:Calmodulin; D018076:DNA, Complementary