Immature Colon Carcinoma Transcript 1 (ICT1)

The adult colon epithelium contains 3 differentiated cell types that arise from a multipotent stem cell. Deviation from the normal maturation pathway by neoplastic transformation is thought to initiate in stem cells or their early descendants. This cDNA represented an mRNA of approximately 900 bp that was downregulated during differentiation of HT29-D4 and Caco-2 colon carcinoma cells and was not influenced by cell density. Southern blot analysis indicated that ICT1 is present as a single copy gene in the human genome. The longest ICT1 cDNA encodes a putative protein of 206 amino acids with a molecular mass of 24 kD. Western blot analysis of HT29-D4 protein extracts using polyclonal antiserum against a synthesized peptide from the C terminus of the putative protein revealed 2 specific bands of 25 and 20 kD.