|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1993 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1992 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Ornithine transcarbamylase [OTC, EC 184.108.40.206]is one of the urea cycle enzymes. There is no physiological necessity for the enzyme in chicken, because chicken is an uricoteric animal. In chicken, however, a few show relatively higher OTC activity in their kidney. The project head established two chicken lines ; one shows higher OTC activity and the other shows no activity in the kidney. Abnormal tissue-specific expression of OTC activity is observed in chicken, i.e., in almost all chicken organs, mRNA of OTC is transcripted and translated, but the translated protein would not be processed by mitochondria in these organs except in the kidney, so that only the kidney shows OTC activity. To elucidate these phenomenon at a molecular level, a molecular cloning of chicken kidney OTC gene is necessary. We have cloned cDNA of chicken kidney OTC and then the nucleotide sequence was determined. The sequence was compared with those of rat liver and of human liver. At the part of mature protein, the sequence of chicken OTC is highly conserved compared with those of rat and human OTC, but at the part of the leader peptide, the difference is obvious. Employing AP-PCR method, the nature of OTC mRNAs in the liver and the pancreas of chicken was investigated. In both organs OTC mRNAs were expressed. However, an experiment using several primer sets suggested that the 5'-DNA sequence of OTC mRNA of both organs differ from that of kidney mRNA.To confirm these results, it would be necessary to get several clones of OTC cDNA from both organs.