PHYSIOLOGICAL FUNCTIONS OF BRANCHED-CHAIN AMINO ACIDS IN MUSCLES

支链α-乙酸脱氢酶（BCKDH）复合物是支链氨基酸（BCAA）分解代谢的限速酶，受特定激酶（BCKDH激酶：BDK）调控。在本研究中，我们的目标是产生肌肉特异性BDK缺陷小鼠，由于BCAA分解代谢加速，可能导致肌肉特异性BCAA缺乏。我们使用Cre-loxP系统生成条件bdk敲除（KO）小鼠；重组ES细胞含有小鼠BDK基因的条件等位基因，该等位基因通过将9-12外显子与loxP位点连接而工程化。因此，外显子9-12被Cre重组酶的表达所删除。在第一次试验中，我们在种系中获得了不含BDK基因的嵌合小鼠。在第二次试验中，我们再次获得了嵌合小鼠，用于产生杂合bdk基因的后代。

Branched-chainα-etoacid dehydrogenase(BCKDH) complex is a rate-limiting enzyme of the branched-chain amino acid(BCAA) catabolism and is regulated by the specific kinase(BCKDH kinase : BDK). In the present study, we aimed to generate muscle-specific BDK deficient mice, which may result in muscle-specific BCAA deficiency due to the acceleration of BCAA catabolism. We used the Cre-loxP system to generate the conditional BDK-knockout(KO) mice ; recombinant ES cells containing a conditional allele of the mouse BDK gene that was engineered by flanking exons 9-12 with loxP sites. Thus, exons 9-12 are deleted by the expression of Cre recombinase. In the first trial, we obtained chimeric mice without the floxed BDK gene in the germ line. In the second trial, we again obtained the chimeric mice, which is used to produce heterozygous BDK-gene-floxed offsprings.