Bone morphogenetic proteins (BMPs), first identified as factors inducing heterogeneous bone and cartilaginous tissues, are now known to play important roles in organogenesis during embryonic development. The amino acids sequences of BMPs are also known to be well conserved from Drosophila to mammalian. So far, BMPs are classified into several subgroups according to their amino acids holomogy. Little is known, however, about the physiologic role and functional sharing of each BMP.In this study, we tried to characterize each BMP's functional sharing by analyzing promoter region of the each BMP gene regardless of the recent classification system based on amino acid homology. The characterization of 5'-flanking region, a promoter structure, is now mostly for the study of the regulation mechanism of gene expression of the specific target gene. By inclusive molecular cloning of the promoter area, we extended the promoter study to 're'-classify a group of genes sharing similar amino acid sequences. Furthermore, we have developed an unique and sensitive in situ hybridization system using a single-stranded DNA probes yielded by polymerase chain reaction (PCR), and used that technique to study how each BMP gene was regulated by transcriptional factors including Hox genes. During this research period, we especially characterized BMP-5 and BMP-6 gene promoters both in normal and pathologic condition as prostate cancer, and found that BMP-6 gene was epigenetically regulated by CpG methylation around the Sp1 transcriptional factor binding sites. On the other hand, BMP-5 lacks such CpG rich area, and regulated by repeated ATTA motifs recognized by Hox genes. As a rule, we performed our studies so that molecular biological assay always went together with morphological analysis. We have presented our data at various international as well as domestic meetings, and publish a lot of scientific papers for academic journals.