大肠癌相关免疫球蛋白新基因SNC73结构与表达研究

目的 研究由减式杂交方法获得的人大肠癌相关基因SNC734 结构和功能。方法 对SNC73的cDNA进行了核苷酸序列测定,分析得到全长序列,并对其编码的蛋白进行了分析及预测;采用In situ-Max荧光原位杂交方法结合荧光R带技术对SNC73在人染色体上的定位作了研究;利用Northern杂交、逆转录聚合酶链反应（RT－PCR）方法检测了SNC73在多种肿瘤细胞系中的表达,及在大肠癌组织与这粘中膜中的表达情况;应用原位杂交／原位PCR技术检测SNC73 mRNA在肠上皮中的表达情况。结果 对SNC73序列及开放阅读框9ORF）进行分析,发现其与免疫球蛋白IgA高度同源,为一免疫球蛋白样基因。该基因定位于人染色体14q3 2。SNC73在大肠癌组织也 肠粘膜的表达有差异（P＜0.05）。SNC73在肠上皮表达阳性。结论 SNC73在大肠癌中低表达,可能为一新的肿瘤标记物,并提示上皮细胞、非淋巴细胞存在IgA类的蛋白。

Structure and expression of colorectal cancer related Immmumoglobulin novel gene SNC73

Objective To study the structure and function of a colorectal cancer associated gene SNC73 obtained by subtractive hybridization technique. Methods Direct sequencing was performed on cDNA of SNC73 gene. In situ max fluorescence in situ hybridization was used in chromosome mapping of SNC73. Expression of SNC73 in various cancer cell lines and differential expression between normal mucosa and colorectal cancer tissue were examined by Northern blotting and RT PCR. Expression of SNC73 in colorectal epithelium was detected by in situ hybridization and in situ PCR. Results Open reading frame prediction showed that SNC73 encodes a peptide identical to the constant region of an IgA molecule in the carboxyl terminus. The gene was mapped to human chromosome 14q32. The expression of SNC73 in colorectal cancer tissue and that in normal mucosa was different ( P <0.05). SNC73 was lowly expressed in colorectal epithelium. Conclusion Decrease in SNC73 expression may be a potential genetic marker for the development of colorectal cancer. An immunoglobulin alpha 1 gene can be expressed in non lymphoid cells.