Modulated expression of human homeobox genes in differentiating intestinal cells

Homeobox genes (Hox genes) control segmentation and segment specificity in Drosophila. Hox genes have been detected in several species from insects to vertebrates. Differential and stage-related expression has been observed in human embryonic tissues as well. We have investigated whether the cell line Caco-2 and human adult intestine express Hox genes. Caco-2 is a cell line derived from a human colon carcinoma and exhibits a spontaneous enterocytic differentiation after cellular confluency in vitro. At 7, 14 and 21 days after seeding we have found that Hox-2.3 and one Hox-3 gene hybridize to poly(A)+RNA in a stage-related fashion. Moreover, the 21 days pattern of hybridization resembles that one observed in adult small intestine. The Caco-2 cell line provides a model system that allows a detailed analysis of cellular factors controlling transcription and stability of Hox gene products.