Quantitative abnormalities and molecular biological investigation of the ADP/ATP carrier protein in J-2-N cardiomyopathic hamsters

ADP/ATP载体蛋白(AAC)位于线粒体内膜，在线粒体能量代谢中起着重要作用。ATP通过AAC从基质转运到细胞质，而ADP则由AAC逆向转运。用Bio14.6仓鼠、本实验室培育的J-2-N心肌病仓鼠和金黄地鼠的心肌组织进行克隆。与金黄地鼠相比，J-2-N仓鼠的AAC竞赛显著减少。用聚合酶链式反应从人成纤维细胞的cDNA文库中克隆出AAC基因，并将人的AAC基因用于筛选金黄地鼠的AAC基因。从各品系仓鼠心肌中提取基因组DNA，构建DNA文库。从这些文库中，我们成功地获得了金黄地鼠心脏AAC的基因组DNA。同时进行RNA斑点杂交分析。金黄地鼠的AAC基因表达水平最高，其次是血清CK水平较高的J-2-N，血清CK和Bio14.6水平较低的J-2-N。这些结果提示，AAC基因表达水平降低是J-2-N心肌病仓鼠心脏代谢异常的机制之一。

The ADP/ATP carrier protein(AAC), located in the mitochondrial inner membrane, plays an important role in the mitochondrial energy metabolism. ATP is transported from matrix to cytoplasm by AAC and at the same time ADP is transported inversely. Cloning was performed using myocardium from Bio14.6 hamsters, J-2-N cardiomyopathic hamsters bred in our laboratory, and Golden hamster. The AAC contest was significantly decreased in J-2-N hamsters as compared with Golden hamsters. cDNA of AAC was cloned from cDNA library of the human fibroblast by PCR.The human cDNA was then used to screen Golden hamster AAC cDNA, which was used as a probe in the latter steps. Genomic DNA was prepared from cardiac muscle of the each strain hamster and DNA libraries were constructed. From these libraries, we have succeeded in obtaining genomic DNA of cardiac AAC in hamster. Also RNA dot blot hybridization analysis was performed. The highest mRNA level for AAC was observed in Golden hamster followed by J-2-N with high serum CK, J-2-N with lower serum CK and Bio14.6. These results suggest that decreased mRNA levels of AAC is one of the mechanisms which explain the abnormalities of cardiac metabolism in J-2-N cardiomyopathic hamsters.