Primarily Screening And Analyzing ESTs Differentially Expressed In Rats' Primary Hepatic Cancer

PURPOSE: To reveal the molecular mechanism of carcinogenesis, we screened and analyzed differentially expressed sequence tags (ESTs) in rats'primary hepatic cancer induced by a differential display of messenger RNA (DDRT-PCR) technique.METHODS: Using diethylnitrosamine (DENA) as an induced regent, the animal models of the various periods during the development of SD rats'primary hepatic cancer were made. The rats'were and killed on 14th day, 28th day, 56th day, 77th day, 105th day and 112th day respectively from the first day when the rats were piped drinking and the liver tissue of every rat was taken after killed. DDRT-PCR was used to research the differential expression of the genes between the normal tissue and the morbid tissue. After screened, the differential expressed fragments obtained from the experiments were cloned and sequenced. The results were analyzed by bioinformatics.RESULTS: 12 cDNA fragments were obtained from the experiments. EST-1, EST-3 and EST-5 had extremely low sequence identity with any genes from GenBank database. EST-12 had no similar sequence from rattus norvegicus ESTs database, while it was similar to partial sequence of PKC-alpha gene in the rat build 4 genome database. EST-7 was similar to rattus norvegicus strain BN/SsNHsdMCW mitochondrion gene (100%), its homologous proteins is unknown. EST-11 was similar to tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, eta polypeptide, and the identity was also 100%. The res(tEST-2,EST,EST-6,EST-8,EST-9 and EST-10) had similar sequences in both databases, and all the identities exceeded 97%.CONCLUSIONS: Twelve ESTs differentially expressed during the different periods of liver canceration were obtained, nine of these are known, others are unknown. EST-7 was similar to BN/SsNHsdMCW mitochondrion gene and the identity was 100%. It was the first report of differentially expressed mRNA of BN/SsNHsdMCW mitochondrion gene in all the liver canceration periods, and the complex variation of this gene suggests it may take part in the carcinogenesis and development of primary hepatic cancer and possibly play a part in the mechanism of the cellular multiplication and malignant transformation.