KALMUS, Gerhard W.; BAXLEY, Tamatha; SCEMAMA, Jean-Luc; East Carolina University: Differential Expression of Abd-B-like Genes in the Enterocytic Differentiation of Caco-2 Cells.

The well conserved family of Hox genes code for transcription factors that are active regulators of segmental identity along the anterior-posterior axis in developing embryos. This activity is reportedly seen in the AP axis of the developing digestive tract in chick and mouse where Hox genes exhibit patterns of expression specific to the region of the gut. In the hindgut, the expression of Abd-B-like genes (paralogs 9-13) seems to be restricted in the mesoderm during differentiation where conducive signaling directs the epithelial transition of the endoderm. Here we investigate the expression of the Abd-B-like genes in the human colon adenocarcinoma cell line Caco-2, which is a well defined model for enterocyte differentiation. RT-PCR and Northern Blot results show differential expression of HoxD10, HoxC12, HoxB13 and HoxD13 when evaluated before and after differentiation. Transcripts for HoxD13 are present during exponential growth but not after differentiation, while HoxC12, HoxD10 and HoxB13 show an increase in transcripts post differentiation. Functional studies will further clarify these genes as potential regulators of proliferation and/or differentiation within this cell model.
This work was supported by the American Cancer Society, Institutional Research Grant ECU 5-89812.