Browsing by Author "Kun Wu"

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    Cloning, tissue distribution and mRNA expression analysis of typeIcollagen alpha 1 gene from Chu's croaker (Nibea coibor)
    (Elsevier, 2022-05-25) Hua Rong; Fan Lin; Lijun Ning; Kun Wu; Baojia Chen; Jia Zheng; Samwel Mchele Limbu; Xiaobo Wen
    The demand for collagen has been increasing over years due to its wide application in food, cosmetics and biomedicine industries. The synthesis of collagen protein in fish depends on instructions provided by collagen, type I, alpha 1 (COL1A1) gene. However, cloning, tissue distribution and mRNA expression of COL1A1 gene in a gel-producing Chu's croaker (Nibea coibor) is currently unknown. This study cloned the cDNA of COL1A1 gene (GenBank accession number: MK641512) from six N. coibor fish. The distribution and mRNA expression pattern of COL1A1 was analyzed in eight tissues of N. coibor. The COL1A1 cDNA had a full length of 6130 bp and contained a 4344 bp open reading frame (ORF) encoding a polypeptide of 1448 amino acids. The homology of N. coibor COL1A1 amino acid had 98% similarity with Larimichthys crocea, indicating conservatism with other members in same family (Sciaenidae). The deduced polypeptide contained the same signal peptides, C-propeptide and N-propeptide domains, and triple helix domains, which are the characteristics of type I collagen in vertebrates. The mRNA of COL1A1 gene was expressed significantly higher in the spine of N. coibor than in all other tissues (P < 0.05), followed by swim bladder, skin and scales. The swim bladder had higher collagen and hydroxyproline contents than other tissues, followed by spine >, scales > and > skin (P < 0.05). Our study successfully cloned the COL1A1 gene from N. coibor for the first time. The COL1A1 gene contained all the features of collagen pro-α1(I) chain proteins, and shared high homology with other marine teleost. COL1A1 gene in N. coibor is highly expressed in spine and swim bladder, consistent with collagen distribution. Our study contributes to better understanding on collagen biosynthesis in N. coibor tissues for various industrial uses.
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    The transforming growth factor beta (TGF-β/Smads) pathway regulates collagen synthesis and deposition in swim bladder of Chu's croaker (Nibea coibor) stimulated by proline
    (2022-09-15) Hua Rong; Fan Lin; Lijun Ning; Kun Wu; Samwel Mchele Limbu; Qingchao Shi; Chuanjie Qin; Xiaobo Wen
    The swim bladder performs various functions in fish, is consumed by humans and can be processed into high-grade fish glue (traditional high-value tonic). However, little is known on the optimum amount of proline (Pro) required for promoting collagen synthesis and deposition in fish swim bladder and the regulatory mechanism. This study explored the effects and optimum amount of dietary Pro supplementation on collagen synthesis and deposition in Chu's croaker (Nibea coibor) swim bladder and its possible molecular mechanism. A total of 450 juvenile fish (8.64 ± 0.14 g) were randomly stocked into 18 cages (25 fish per cage) in triplicate and fed Pro supplemented diets (0, 5, 10, 15, 20 and 25 g kg−1) for eight weeks. Another 225 fish (11.62 ± 0.15 g) were distributed randomly into control, Pro and Pro diet plus injected with specific inhibitor of Smad3 (SIS3) in order to inhibit the transforming growth factor beta (TGF-β)/Smads pathway. Pro supplementation up-regulated significantly the expression of genes involved in TGF-β/Smads pathway such as collagen, type I, alpha 1 (col1a1) and 2 (col1a2), TGF-β and Smad2/3, and increased collagen content in the Chu's croaker swim bladder (P < 0.05). The optimum dietary Pro supplementation for deposition of collagen in Chu's croaker swim bladder was 19.36 g kg−1. The collagen content in the swim bladder positively correlated significantly with the mRNA expression of col1a1, col1a2, TGF-β and Smad2/3 genes (P < 0.05). The optimum dietary Pro supplementation for maximum synthesis of collagen in Chu's croaker swim bladder was 13.25, 13.32 and 15.94 g kg−1 based on mRNA expression of Smads2, Smads3 and col1a2 genes, respectively. SIS3 down-regulated the expression of col1a1, col1a2, TGF-β and Smad2/3 genes, subsequently decreased collagen deposition in the swim bladder (P < 0.05). These results suggest that 13.25 to 19.36 g kg−1 Pro supplementation improve collagen synthesis and deposition in Chu's croaker swim bladder. The TGF-β/Smad signaling pathway regulates collagen synthesis and deposition in Chu's croaker swim bladder. Our results provide an understanding on the molecular mechanism of collagen synthesis and deposition in fish for producing collagen required for human food and fish glue.