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專題討論

題目：第八生長分化因子在雞胚胎發育中扮演之角色
時間：2009年4月9日
地點：畜產系圖書館
講者：沈志隆
摘要：
第八生長分化因子 (myostatin)為一肌肉生長強力抑制子。Myostatin基因剔除會造成骨骼肌的增生與肥大，但myostatin在體內的作用機制仍知之甚少，特別是在雞隻胚胎發育中。數據顯示myostatin活化p21與MyoD這兩個肌肉分化相關基因促進雞胚肌肉前驅細胞的最終分化，藉此控制體內肌肉分裂與分化平衡；但myostatin在肢芽發育時卻抑制MyoD的表現。除此之外，近來報告提出myostatiny在雞胚肌生細胞系建立前 (E3)就已經開始表現 (E1)。藉由即時PCR與反轉錄PCR，myostatin mRNA在雞胚之腦、雞胗、肌肉、心臟、肝、小腸、大腸、中腎、睪丸與卵巢皆有表現。特別的是，除了肌肉細胞myostatin在睪丸與卵巢都有高量表現但其真正功能仍需研究。作者提出雞胚胎發育時myostatin不同之表現與功能源於環境依賴之可能。

(關鍵語：環境依賴、胚胎發育、第八生長分化因子)

Title: Role of myostatin during chick embryonic development
Abstract:
Myostatin is a potent inhibitor of muscle growth. Genetic deletion of myostatin leads to hyperplasia and hypertrophy of skeletal muscle, but the mechanisms of myostatin in vivo are poorly understood especially in chick embryogenesis. The data demonstrate that myostatin acts in vivo to regulate the balance between proliferation and differentiation of chick embryonic muscle progenitors by promoting their terminal differentiation through the activation of p21 and MyoD, two genes associated with muscle differentiation; but myostatin in the developing limb bud prevents the expression of MyoD. In addition, recent studies in chicken embryo suggested that the myostatin was expressed on E1 even before the establishment of myogenic lineage on E3. As revealed by real-time PCR and RT-PCR, the mRNA of myostatin was detected in brain, eye, gizzard, muscle, heart, liver, small gut, large gut, mesonephroi, testis and ovary of chick embryos. In particular, myostatin was highly expressed in testis and ovary other than muscle, but the real functions need to investigate. The authors propose that different expression and function of myostatin in embryogenesis of chicken is likely to be context-dependent.
(Key Words: Context-Dependent, Embryogenesis, Myostatin)

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