Identification of region-specific genes in the early chicken endoderm

In vertebrates, the endoderm gives rise to the epithelial lining of the digestive tract, respiratory system and endocrine organs. After gastrulation, the newly formed endoderm gradually becomes regionalized and differentiates into specific organs. To understand the molecular basis of early endoderm regionalization, which is largely unknown, it is necessary to identify novel region-specific genes as candidates potentially involved in this process. Applying an Affymetrix Array based approach we aimed for the identification of genes specifically upregulated in the foregut or mid-/hindgut endoderm at the onset of regionalization. Several genes exhibiting spatial and temporal restricted expression patterns in the developing early endoderm were identified and their expression was validated via RT-PCR and whole mount in situ hybridization. We report here the detailed gene expression patterns of two novel genes specifically associated with foregut endoderm and of eight novel genes specifically expressed in the mid-/hindgut endoderm at HH stages 10-11. Future functional analysis of these genes may help to elucidate the mechanisms involved in endoderm development and regionalization.