[Molecular cloning and alternative splicing analysis of hepatoma associated gene HTA].

Objective: To obtain the full length cDNA sequences of hepatoma associated gene HTA, analyze its alternative splicing, detect the expression pattern of 2 HTA gene transcripts in different hepatic cell lines, and to establish a base for further study of HTA gene function in hepatocellular carcinoma (HCC) occurrence and development.

Methods: The full length cDNA of HTA gene was cloned by rapid amplification of cDNA 3' ends (3'-RACE), rapid amplification of cDNA 5' ends (5'-RACE) and DNA sequencing. The gene structure and alternative splicing were analysed. Northern blot assay was performed to detect the expression pattern of 2 HTA gene transcripts in different hepatic cell lines.

Results: The full length of HTA gene was 1414 bp, composed of 3 exons and 2 introns, and the second intron could be retained in mRNA. Northern blot assay showed that 2 transcripts of HTA mRNA(1.4 kb and 1.7 kb) could express in the HCC cell lines HepG2 and QGY-7703, but not in the non-malignant cell line L-02 and HUVEC. The expression level of 1.4 kb transcript was much higher than 1.7 kb one.

Conclusion: This study successfully has obtained the full length cDNA of HTA gene, and analysed the gene sequence and alternative splicing, 2 transcripts of HTA mRNA specifically expressed in HCC cell lines. As a hepatoma associated gene, HTA deserves further investigation.