Peptide gene expression in gastrointestinal mucosal ulceration: ordered sequence or redundancy?

Many genes, some encoding peptides, are upregulated after mucosal damage in the gastrointestinal mucosa: we have looked for an ordered sequence in the expression of genes such as c-fos, c-jun, egr-1, Sp-1, epidermal growth fa ctor, transforming growth factors alpha and beta, trefoil peptides, epiderm al growth factor receptor, hepatocyte growth factor, c-met, fibroblast grow th factor, platelet derived growth factor, and vascular endothelial growth factor. All of these gene products play an important reparative role, assis ting appropriate healing of the damaged mucosa. There does indeed seem to b e a temporal sequence in this gene expression, but there is a certain degre e of redundancy within the system, both in terms of receptor binding and th e function of the gene products. However, it is probable that the integrate d function of these genes and their products safeguard the important healin g properties of the gastrointestinal mucosa. Although the function of indiv idual gene products is of course important, it now stems critical to explor e the inter-relations between these genes and their encoded products to exp lain fully mucosal regeneration after damage.