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.