DETERMINATION OF THE TRANSCRIPTION INITIATION SITE OF-THE CARBAMYL PHOSPHATE SYNTHETASE I GENE

Carbamyl phosphate synthetase I (CPSI for short )is the first key enzyme of the urea cycle and mainly located in mitochondria of hepatocytes. It is the tissue specific enzyme of liver and involved in the differentiation of hepatocytes. We have observed the decrease of the activity of CPSI during hepatocarcinogenesis. A series of experiments suggest that CPSI gene be regulated at transcriptional level. Transcription regulation of eukaryotic genes is mediated by interaction of trans-acting factors and cis-acting elements. Cis-acting elements are mainly