INTRODUCTION. Protein families are distinguished by members that exhibit sequence and biomedical function similarity. For most gene changes in protein abundance are related to changes in mRNA abundance, which are immensely informative about cell state and the activity of genes. LifeExpress RNA (LE) database (Incyte Genomics, Inc) is a large-scale genome expression database. Based on LE we derived the functional relationship of Pfam[1], a database of protein domain families, by studying the global expression profile of the corresponding genes of Pfam family members. The expression profiles for 135 largest Pfam families were summarized and relationships were analyzed. The study present a simple model for conceptualizing the complex genetic regulatory network.