Cloning and analysis of the human Pax-5 gene promoter

The expression of Pax-5 gene is altered in human myeloma cells (malignant plasma cells). This altered expression is considered to be closely involved in oncogenesis of human myeloma. To investigate the possible mechanism(s) underlying this alteration, we first cloned the 1,050 bp fragment in the 5' upstream region of human Pax-5 gene by PCR-mediated gene walking method. The cloned fragment has predicted regulatory motifs for Lyf-1(Ik-1), IK-2, bHLH, E-47, Sox-5, Oct-1, GATA-1,-2, and -3, but it lacks a TATA box. By constructing deletion mutants of this fragment, its basal promoter activity was analyzed by transfecting these mutants to Cos 7 cells. The maximal promoter activity was recovered by the fragment that extends between -70 to -820 upstream of the transcription start site. Also, three DNA fragments from this cloned sequence were used as templates in gel shift assay; these fragments covered most of the predicted regulatory sites. Specific binding activities were found in each DNA fragment. Therefore, we could clone the functionally active fragment of 5' upstream region of human Pax-5 gene.