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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2008.04.022 Byline: Jie Mei (a), Qi-Ya Zhang (a), Zhi Li (a), Shuo Lin (b), Jian-Fang Gui (a) Keywords: C1q-like factor; p53; Caspase 3/9; Brain; Zebrafish; Apoptosis; G2/M phase arrest; Hematopoiesis Abstract: Except for the complement C1q, the immunological functions of other C1q family members have remained unclear. Here we describe zebrafish C1q-like, whose transcription and translation display a uniform distribution in early embryos, and are restricted to mid-hind brain and eye in later embryos. In vitro studies showed that C1q-like could inhibit the apoptosis induced by ActD and CHX in EPC cells, through repressing caspase 3/9 activities. Moreover, its physiological roles were studied by morpholino-mediated knockdown in zebrafish embryogenesis. In comparison with control embryos, the C1q-like knockdown embryos display obvious defects in the head and craniofacial development mediated through p53-induced apoptosis, which was confirmed by the in vitro transcribed C1q-like mRNA or p53 MO co-injection. TUNEL assays revealed extensive cell death, and caspase 3/9 activity measurement also revealed about two folds increase in C1q-like morphant embryos, which was inhibited by p53 MO co-injection. Real-time quantitative PCR showed the up-regulation expression of several apoptosis regulators such as p53, mdm2, p21, Bax and caspase 3, and down-regulation expression of hbae1 in the C1q-like morphant embryos. Knockdown of C1q-like in zebrafish embryos decreased hemoglobin production and impaired the organization of mesencephalic vein and other brain blood vessels. Interestingly, exposure of zebrafish embryos to UV resulted in an increase in mRNA expression of C1q-like, whereas over-expression of C1q-like was not enough resist to the damage. Furthermore, C1q-like transcription was up-regulated in response to pathogen Aeromonas hydrophila, and embryo survival significantly decreased in the C1q-like morphants after exposure to the bacteria. The data suggested that C1q-like might play an antiapoptotic and protective role in inhibiting p53-dependent and caspase 3/9-mediated apoptosis during embryogenesis, especially in the brain development, and C1q-like should be a novel regulator of cell survival during zebrafish embryogenesis. Author Affiliation: (a) State Key Laboratory of Freshwater Ecology and Biotechnology, Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan 430072, China (b) Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095, USA Article History: Received 5 September 2007; Revised 15 April 2008; Accepted 15 April 2008

Abstract Background A virus was isolated from diseased turbot Scophthalmus maximus in China. Biophysical and biochemical assays, electron microscopy, and genome electrophoresis revealed that the virus belonged to the genus Aquareovirus, and was named Scophthalmus maximus reovirus (SMReV). To the best of our knowledge, no complete sequence of an aquareovirus from marine fish has been determined. Therefore, the complete characterization and analysis of the genome of this novel aquareovirus will facilitate further understanding of the taxonomic distribution of aquareovirus species and the molecular mechanism of its pathogenesis. Results The full-length genome sequences of SMReV were determined. It comprises eleven dsRNA segments covering 24,042 base pairs and has the largest S4 genome segment in the sequenced aquareoviruses. Sequence analysis showed that all of the segments contained six conserved nucleotides at the 5' end and five conserved nucleotides at the 3' end (5'-GUUUUA ---- UCAUC-3'). The encoded amino acid sequences share the highest sequence identities with the respective proteins of aquareoviruses in species group Aquareovirus A. Phylogenetic analysis based on the major outer capsid protein VP7 and RNA-dependent RNA polymerase were performed. Members in Aquareovirus were clustered in two groups, one from fresh water fish and the other from marine fish. Furthermore, a fusion associated small transmembrane (FAST) protein NS22, which is translated from a non-AUG start site, was identified in the S7 segment. Conclusions This study has provided the complete genome sequence of a novel isolated aquareovirus from marine fish. Amino acids comparison and phylogenetic analysis suggested that SMReV was a new aquareovirus in the species group Aquareovirus A. Phylogenetic analysis among aquareoviruses revealed that VP7 could be used as a reference to divide the aquareovirus from hosts in fresh water or marine. In addition, a FAST protein with a non-AUG start site was identified, which partially contributed to the cytopathic effect caused by the virus infection. These results provide new insights into the virus-host and virus-environment interactions.