Identification of evolutionarily invariant sequences in the protein C genepromoter

Recent studies on human protein C gene expression have revealed the presenc e of three transcription factor binding sites in close proximity to the tra nscription start site. Binding sites for the liver-enriched hepatocyte nucl ear factors 1 and 3 (HNF-1 and HNF-3, respectively) are located immediately upstream of the transcription start site, whereas just downstream of the s tart site a presently unidentified transcription factor may bind. To identi fy other candidate transcription factor binding sites in the protein C prom oter, we studied the promoter sequence identity in a number of evolutionari ly close and more distant species: Gorilla gorilla, Pongo pygmaeus, Pan tro glodytes, Homo sapiens, Cebus apella, Macaca mulatta, Callithrix jacchus, P apio hamadryas, Macaca fascicularis, and Rattus norvegicus. This analysis s howed that a high degree of identity (78%) exists among the different prima tes. Comparison of the primate consensus sequence with the Rattus norvegicu s protein C promoter sequence revealed the presence of seven identical regi ons (I to VII). Two of these regions overlap with established regulatory se quences for HNF-3 and HNF-1 (region VI) and for PCE-1 (region VII), respect ively. The functional importance and the transcription factors that may bin d to the other five identical regions are now to be determined.