Genetical and toxicological studies for evaluation of clinical tests in individualities

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There are two rat strains which showed different serum leucine amino-peptidase activity, one of the clinical tests, and the difference was turned to be genetically controlled by the experiments using F1 and F2 as well as back-crossed rats. Bcause N-terminal 20 amino acid sequences were available and conserved among human, bovine and rat, we made the primers within the conserved region, amplified DNA by PCR using rat liver cDNA library. PCR product showed the expected size but no sequence similarity to conserved amino acids. We are trying PCR using other promers, and also other cDNA libraries.LAP activity is higher in certain tumor cells and requires zinc. We next examined the relation between cell transformation and metallothionein (MT) which is thought to function as zinc metabolism. Because MT expression is controlled transcriptionally, MT I promoter was inserted upstream of the reporter gene (lacZ) and the resulting plasmid was introduced to normal cells as well as transformed cells including one of the ras, sis or neu oncogene. After treatmer of metal or glucocorticoid, beta-galactosidase activity was induced in normal and ras-transformed cells, superinduced in sistransformed cells, but repressed in neu-tranformed cells. Highter MT content was also thought to cause the resistance to Cisplatin which is one of cancer chemotherapeutic agents. ras, sis, neu transformed cells showed higher resistance to Cisplatin compared to normal cells. From these results, we concluded that MT gene expression was controlled by MT I promoter which was induced by ras and sis oncogene, and might be controlled by MT II promoter or other factors in ne transformed cells.