title: Molecular and acute temperature stress response characterizations of caspase-8 gene in two mussels, Mytilus coruscus and Mytilus galloprovincialis.
abstract: The caspase family represents aspartate-specific cysteine proteases that play key roles in initiation of apoptosis in various cells response to environmental stress. In this study, two caspase-8 cDNA sequences were cloned from two Mytilus mussels, Mytilus coruscus (Mccaspase-8) and Mytilus galloprovincialis (Mgcaspase-8), respectively. The full-length cDNA of Mccaspase-8 was 1884bp, including a 5'-terminal untranslated region (UTR) of 140bp, a 3'-terminal UTR of 238bp and an open reading frame (ORF) of 1506bp encoding a polypeptide of 501 amino acids. The 1775bp full-length Mg caspase-8 cDNA sequence contained an ORF of 1488bp encoding a polypeptide of 495 amino acid residues, a 5'-UTR of 51bp and a 3'-UTR of 236bp. Both the Mccaspase-8 and Mgcaspase-8 amino acid sequences contained two highly conservative death effector domains (DEDs) at N-terminal, the caspase family domains P20 and P10 and the caspase family cysteine active site 'KPKLFFIQACQG'. Phylogenetic analysis revealed that Mccaspase-8 and Mgcaspase-8 were clustered with the caspase-8 from other organisms, with the close relationship with caspase-8 from mollusk. Quantitative real-time reverse transcription PCR (qRT-PCR) analysis indicated that the predominant transcripts of Mccaspase-8 were in mantle and gonad tissue of M. coruscus and the high expression levels of Mgcaspase-8 were in digestive gland and gill tissue of M. galloprovincialis, respectively. The impacts of temperature stress on Mccaspase-8 and Mgcaspase-8 expressions were tested in gill tissue and hemocytes of both species. Our results showed that both Mccaspase-8 and Mgcaspase-8 transcripts and caspase-8 activity in gill tissue and hemocytes could be induced significantly after cold and heat stress (p<0.05) and that these responses different between tissues and species. These results suggested that caspase-8 might play an important role in response to temperature stress and in determining cellular thermal tolerance limits in M. coruscus and M. galloprovincialis.
authors.affiliation: Key Laboratory of Healthy Mariculture for East China Sea, Ministry of Agriculture of the P.R.C, Fisheries College, Jimei University, Xiamen 361021, China.
authors.forename: Duo
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Healthy Mariculture for East China Sea, Ministry of Agriculture of the P.R.C, Fisheries College, Jimei University, Xiamen 361021, China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Wang
authors.affiliation: Key Laboratory of Healthy Mariculture for East China Sea, Ministry of Agriculture of the P.R.C, Fisheries College, Jimei University, Xiamen 361021, China. Electronic address: clyao@jmu.edu.cn.
authors.forename: Cui-Luan
authors.initials: CL
authors.lastname: Yao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D053181:Caspase 8 / Q000235:genetics* / Q000378:metabolism; D005880:Gills / Q000201:enzymology*; D006434:Hemocytes / Q000201:enzymology; D008969:Molecular Sequence Data; D049878:Mytilus / Q000201:enzymology / Q000235:genetics*; D009928:Organ Specificity; D010802:Phylogeny; D013045:Species Specificity; D013312:Stress, Physiological; D013696:Temperature; D059467:Transcriptome
chemical_list: D053181:Caspase 8
keywords: Caspase-8; Mytilus; Temperature stress