ABSTRACT
Red tilapia has become more popular for aquaculture production in China in recent years. However, the pigmentation differentiation that has resulted from the process of genetic breeding and skin color variation during the overwintering period are the main problems limiting the development of commercial culture. The genetic basis of skin color differentiation is still not understood. Solute carrier family 7 member 11 (slc7a11) has been identified to be a critical genetic regulator of pheomelanin synthesis in the skin of mammals. However, little information is available about its molecular characteristics, expression, location and function in skin color differentiation of fish. In this study, three complete cDNA sequences (2159â¯bp, 2190â¯bp and 2249â¯bp) of slc7a11 were successfully isolated from Malaysian red tilapia, encoding polypeptides of 492, 525 and 492 amino acids respectively. Quantitative real-time PCR demonstrated that slc7a11 mRNA expression is high in the ventral skin of PR (pink with scattered red spots) fish. Immunofluorescence analysis revealed that xCT (the protein encoded by slc7a11) was concentrated mainly in the cytoplasm and nucleus of both the dorsal and ventral skin cells of fish. After RNA interference of slc7a11, slc7a11 and cbs mRNA expressions decreased, but the tyr mRNA expression increased in the skin of fish. Results suggest that slc7a11 plays an important role in skin color formation and differentiation of red tilapia through the melanogenesis pathway.
Subject(s)
Amino Acid Transport System y+/genetics , Fish Proteins/genetics , Skin Pigmentation/genetics , Tilapia/genetics , Amino Acid Sequence , Amino Acid Transport System y+/chemistry , Amino Acid Transport System y+/metabolism , Animals , Base Sequence , DNA, Complementary/genetics , Gene Expression Regulation , Phylogeny , Protein Transport , RNA Interference , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sequence Analysis, DNA , Skin/metabolismABSTRACT
Cdc2 kinase is a catalytic subunit of the maturation-promoting factor (MPF), a central factor for inducing the meiotic maturation of oocytes. MPF has been studied in a wide variety of animal species; however, its expression in crustaceans is poorly characterized. In this study, a complete cDNA sequence of Cdc2 kinase was cloned from the red claw crayfish, Cherax quadricarinatus, and its spatiotemporal expression profiles were analyzed. The Cdc2 cDNA (1,769 bp) encodes for a 299 amino acid protein with a calculated molecular weight of 34.7 kDa. Quantitative real-time PCR demonstrated that Cdc2 mRNA was expressed mainly in the ovary tissue and the expression decreased as the ovaries developed. Immunohistochemistry analysis revealed that the Cdc2 protein relocated from the cytoplasm to the nucleus during oogenesis. These findings suggest that Cdc2 kinase may play an important role in the gametogenesis and gonad development in C. quadricarinatus.
Subject(s)
Arthropod Proteins/genetics , Astacoidea/enzymology , CDC2 Protein Kinase/genetics , Oogenesis , Amino Acid Sequence , Animals , Arthropod Proteins/metabolism , Arthropod Proteins/physiology , Astacoidea/cytology , Astacoidea/genetics , Base Sequence , CDC2 Protein Kinase/metabolism , CDC2 Protein Kinase/physiology , Female , Gene Expression , Gene Expression Regulation, Developmental , Gene Expression Regulation, Enzymologic , Male , Molecular Sequence Data , Organ Specificity , Ovary/cytology , Ovary/enzymology , Ovary/growth & development , Phylogeny , Protein Subunits/genetics , Protein Subunits/metabolism , Protein Subunits/physiology , Sequence Analysis, DNA , Sequence Homology, Amino AcidABSTRACT
In this study, we explored the pathogenic mechanism of white spot syndrome virus (WSSV) in crayfish, Cherax quadricarinatus, by investigating activities of enzymes related to innate immune function during infection. After 6-12 h of exposure to WSSV, the activities of four enzymes, phenoloxidase (PO), peroxidase (POD), superoxide dismutase (SOD) and lysozyme (LSZ), increased in the gills of C. quadricarinatus but then sharply decreased during longer infection times. Except for PO, the activities of other enzymes in the WSSV-infected crayfish (Group II) were significantly lower than those of the controls at 72 h post-exposure (P < 0.01). Interestingly, the enzyme activities in the group treated with polysaccharides before challenge with WSSV (Group III) were higher than those in Group II. This phenomenon demonstrated that the polysaccharides could improve the immuno-enzyme activities and enhance the organism's antiviral defenses. Morphological examination by transmission electron microscopy revealed abundant WSSV particles and significant damage in the gills of infected crayfish. WSSV infection caused parts of the gill epithelium and microvilli to be reduced in number and size or damaged; meanwhile, the mitochondria morphology changed, with parts of the cristae diminished leaving large vacuoles. Moreover, electron dense deposits appeared and heterochromatinized nuclei could be seen in blood cells with ruptured nuclear membranes and outflow of nucleoplasm. The findings of this study furthers our understanding of the biochemical alterations induced by viral infections, including changes in the antioxidant status, oxidative stress and lysozyme activity, which could help to advance strategies for control of WSSV in crayfish.
