Bone morphogenetic protein 2 transcripts in rapidly developing deer antler tissue contain an extended 5' non-coding region arising from a distal promoter

To understand the regulation of the BMP-2 gene expression, we recently isolated the BMP-2 gene from a mouse genomic library and characterized the exon-intron structure and promoter. RNase protection assay using poly (A)⁺ RNA of mouse osteoblasts demonstrates that two regions in BMP-2 gene are protected by antisense mouse BMP-2 RNA probes. These results demonstrate that BMP-2 gene utilizes two alternative promoters, a distal and a proximal promoter. In the present study we demonstrate that BMP-2 mRNA from rapidly growing deer antler tissue has an extended 5' non-coding region compared with the human and rat BMP-2 mRNA. The extended 5' non-coding region in the deer mRNA represents transcripts from the upstream distal promoter. This is the first evidence of a natural BMP-2 mRNA from a bone-forming tissue that most likely initiated from the distal transcription start site.