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

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.

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.

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.

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.