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標題: TGF-β家族對肌肉細胞生長之影響
The Effects of TGF-β Superfamily on the Capacity of Muscle Cell Growth
作者: 吳雅純
Wu, Ya-Chun
關鍵字: TGF-β superfamily;變化與生長因子之β 家族;GDF-8;C2C12 myoblast;第八生長分化因子;C2C12 肌原細胞
出版社: 畜產學系
Transforming growth factor-beta (TGF-β) 家族 (superfamily) 由一群調控細胞生長與分化之因子所組成。由雙倍肌肉 (double-muscled) 表型肉牛與基因剔除 (knock-out) 小鼠的研究中得知 TGF-β 家族中的 growth differentiation factor-8 (GDF-8) 基因對肌肉生長影響甚鉅,因此該基因對豬肌肉組織生長的影響值得深入探討。本研究中首先證實 GDF-8 基因專一表現於豬之肌肉組織,並比較不同豬品種間 GDF-8 基因序列及分析其在肌肉組織中之表現量,結果顯示在生長與產肉效能差異極鉅之藍瑞斯、杜洛克、桃園豬與小耳種豬等豬品種間的肌肉組織中 GDF-8 基因的表現量並無顯著差異,且在 GDF-8 基因 3' 端之核酸序列並無豬品種間之差異性,更進一步比較杜洛克與桃園豬完整 GDF-8 基因顯示二者之核酸序列完全相同。
本試驗將GDF-8 與另一個TGF-β家族成員 bone morphogenetic protein-4 (BMP-4) 之完整 cDNA 序列構築入可在哺乳動物細胞表現之載體中。含GDF-8 與 BMP-4 基因之缺失及為阻斷該基因表現之 antisense 寡核酸鏈的表現載體也被構築出來。將上述表現載體分別以轉形入小鼠 C2C12 肌原細胞株中,以探討這兩個基因表現對肌原細胞生長之影響。結果顯示利用 antisense 抑制 GDF-8 或 BMP-4 基因表現載體之處理組中,可顯著促進肌原細胞之生長,而這種效應也可由單純轉形 GDF-8 或 BMP-4 基因之 antisense 寡核酸鏈的試驗中獲得印證;經轉形缺失型 GDF-8 基因之細胞,其生長不僅受到抑制,部分細胞分化成類造骨細胞之外貌,這種效應並不存在於 BMP-4 缺失基因轉形之肌原細胞中。

Transforming growth factorβ (TGF-β) superfamily encompasses a large group of growth and differentiation factors. The studies of the GDF-8 in gene-null mice and double muscle cattles showed that GDF-8 was predominantly expressed in skeletal muscle and had made a great influence on skeletal muscle growth. It is worthy to be explored the role of GDF-8 in productive performances of pigs. In the present study, expression of GDF-8 gene was firstly determined and showed tissue-specific expression in skeletal muscles of pigs. Amount of expression and nucleotide sequence of GDF-8 gene amoung Landrace, Duroc, Taoyuan and Small-ear were evaluated. These pig breeds posses significant phenotypes in growth rate and muscle production responded from the genetic background. The data showed that the amount of GDF-8 gene expression in skeletal muscles of pigs was insignificantly different and all of the nucleotide sequences in 3'-terminal reagion of GDF-8 gene were the same.
GDF-8 and another gene belonged to TGF-β superfamily, bone morphogenic protein-4 (BMP-4), were cloned and constructed into a mammalian expression vector, respectively. The expression vectors constructed with the deletion and antisense oligonucleotide of both genes were also produced. All of the expression vectors were transfered into C2C12 myoblast of mouse by liposome-mediated transfection for studying the effects of cell growth due to the certain gene products. Results showed that the capacity of cell growth was stimulated due to the transfection of GDF-8 or BMP-4 antisense vectors, the products of endogenous both genes were proposed reduction by treatments. Such effects were similar to the result of C2C12 cells transfected with naked antisense oligomers of GDF-8 or BMP-4 genes. The growth of C2C12 myoblasts transfected with the deletion expression vector of GDF-8 were restrict. Partial of above were differentiation into osteoblast-like lineage, but this effect was absent in the transfected cells with BMP-4 deletion expression vector.
Appears in Collections:動物科學系

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