CHARACTERIZATION OF THE 5'-FLANKING REGION OF THE HUMAN TARTRATE-RESISTANT ACID-PHOSPHATASE (TRAP) GENE

Tartrate-resistant acid phosphatase (TRAP) is expressed at high levels in osteoclasts and may play an important role in the bone resorptive process, However, factors regulating human TRAP gene expression have n ot been clearly defined. Therefore, we isolated a genomic clone (CL-9) for TRAP containing a 14-kb insert, A restriction map was generated f or this insert, and a 2,6-kb ApaI fragment containing the 5'-flanking region was subcloned, Sequence analysis of this fragment revealed the presence of candidate transcription factor-binding sequences for H-APF -1, SP1, GATA2, and the c-Myc proto-oncogene, PCR analysis of RNA isol ated from human osteoclastomas and pagetic bone revealed a 276-bp intr on at -1 bp to -276 bp relative to the ATG and a transcript originatin g from this intron. Rapid amplification of the 5' end of the human TRA P mRNA by PCR indicated the presence of a 93-bp untranslated region 5' from the intron. Promoter activity was detected in the DNA fragment f rom +1 bp to -1903 bp relative to the ATG initiation codon, which drov e the transient expression of a luciferase reporter gene when transfec ted into HRE H9 rabbit endometrial cells. Comparison of the human TRAP 5'-flanking region with mouse TRAP and uteroferrin revealed 41% and 4 7% homology, respectively. This suggests that regulation of human TRAP gene expression may differ from that for the murine TRAP gene.