FIG. 1.

Aromatase gene expression and promoter activity in bone cells. (A) Expression of exons I.4 and I.6 in primary cultured human mesenchymal stem cells (hMSCs), the human chondrocyte HCS-2/8 cell line, primary cultured human chondrocytes (chondrocyte), and human osteosarcoma HOS cells and MG63 cells. RT-PCR was performed by using specific primers derived from the sequence of the coding region from exon I.4 or exon I.6 to exon II of the human aromatase gene. The expected PCR products (220 bp and 240 bp) were identified by 2% agarose gel electrophoresis. The top and bottom arrows indicate exon I.6 and exon I.4, respectively. The 1-kb bands seen in chondrocytes and HOS cells are contaminating genomic DNA (stars). (B) Sequences of transcripts for exons I.4 and 1.f linked to exon II. A novel transcript of the aromatase gene 5′-UTR corresponding to exons I.4 and I.f linked to exon II was observed for the human chondrocyte HCS-2/8 cell line (arrowhead in panel A). Boxes indicate exon-intron junctions, and the ATG (italic type) in each transcript indicates the translation start site. M, 1-kb molecular size ladder.