PDK4基因在骨骼肌发育中功能的初步探讨

【作者】 菅记涌；

【导师】 朱大海；

【作者基本信息】 中国协和医科大学 ， 生物化学与分子生物学， 2008， 硕士

【摘要】 生物体的一切生命活动的本质是新陈代谢。能量和物质在生物体内不断流动,并通过化学反应网络系统为各种生命活动提供能量。而生物体内的新陈代谢并不是完全自发进行的,而是靠生物催化剂—酶来催化的。本研究以肉鸡和蛋鸡作为模式生物,对我室使用芯片在肉鸡和蛋鸡骨骼肌中发现的一个差异表达基因进行了验证,并对该差异基因进行初步的功能研究,为解释蛋鸡肉鸡巨大表型差异提供线索。PDK4在骨骼肌糖代谢中发挥重要功能。本室芯片结果显示PDK4在肉鸡和蛋鸡骨骼肌中差异表达。Real-Time PCR进一步验证了芯片的结果,PDK4在蛋鸡和肉鸡出生后发育过程中呈动态表达。并且,我们发现PDK4表达水平变化与肉鸡的出生后骨骼肌快速生长曲线呈负相关,但在蛋鸡中并未发现这一现象。PDH酶活性在蛋鸡和肉鸡的出生后发育过程中的变化趋势的研究表明,PDH酶活性与肉鸡的生长曲线相一致而在蛋鸡中不符。这更进一步证明了,PDK4在肉鸡的快速生长中发挥了一定的作用。在鸡骨骼肌原代细胞分化过程中,PDK4表达水平和PDH酶活性在一定程度上揭示了PDK4在肉鸡的出生后发育中的作用。过表达PDK4并不能影响鸡骨骼肌原代细胞的增殖,这一结果提示PDK4单独作用并不足以促进肉鸡的出生后快速增长。综上,本研究发现一个糖代谢过程中的酶—PDK4,与肉鸡出生后的骨骼肌快速增长密切相关。在能量代谢水平上,本研究为蛋鸡和肉鸡骨骼肌的差异生长提供了部分解释。更多还原

【Abstract】 The essential characteristic of biological life is metabolism. It is the incessant flow of energy and matter through a network of chemical reactions that enable the living organism to generate all kinds of activities. The metabolism is not a spontaneous reaction and is catalyzed by the enzymes. To give an insight into the molecular mechanism of postnatal development, broiler and layer chicken have been utilized as animal model because of their significant difference in skeletal muscle growth rate. So broiler needs much more energy to maintain the high muscle growth rate. Some metabolic enzyme must be differentially expressd between broiler and layer. Our lab used microarray data to analysis the differential muscle growth of broiler and layer after hatch.Pyruvate dehydrogenase kinase 4 (PDK4) plays an important role in the glycolysis. The regulation of PDC activity by PDK determines and reflects substrate preference and is critical to the ’glucose-fatty acid cycle’ to maintain glucose homoeostasis. Real-time PCR demonstrated that PDK4 was differentially expressed between layer and broiler, which were consistent with the result of microarray. We have identified a negative correlation for muscular PDK4 gene expression with the postnatal rapid growth of broiler and the Pyruvate dehydrogenase (PDH) activity during the post-hatch development is coincident with its mRNA expression pattern, but not in layer. The PDK4 expression pattern and the PDH enzyme activity during the muscle cells differentiation in vitro indicated that PDK4 gene was partially involved in the broiler rapid growth. Finally, to assess whether PDK4 is the direct regulator of broiler postnatal muscle growth, we investigated whether PDK4 could affect the cell cycle. Our data demonstrate that PDK4 itself was not enough to initiate the rapid muscle growth of broiler. However, the correlation between the PDK4 expression level of broiler and its growth rate also told us that PDK4 was the genetics selected gene which contributed to the broiler postnatal growth. Overall, our results first indicate that PDK4 gene expression is correlated to the broiler muscle growth. Our researches try to elucidate the possible role of PDK4 in the broiler muscle rapid growth. And the researches would help to explain the big difference between broiler and layer postnatal muscle development.更多还原