title: Transactivation of human osteoprotegerin promoter by GATA-3.
abstract: Osteoprotegerin (OPG) is a key regulator of bone remodeling. Mutations in OPG are involved in a variety of human diseases. We have shown that cochlear spiral ganglion cells secrete OPG at high levels and lack of OPG causes sensorineural hearing loss in addition to the previously described conductive hearing loss. In order to study the regulation of OPG expression, we conducted a database search on regulatory elements in the promoter region of the OPG gene, and identified two potential GATA-3 binding sites. Using luciferase assays and site directed mutagenesis, we demonstrate that these two elements are GATA-3 responsive and support GATA-3 transactivation in human HEK and HeLa cells. The expression of wild type GATA-3 activated OPG mRNA and protein expression, while the expression of a dominant negative mutant of GATA-3 or a GATA-3 shRNA construct reduced OPG mRNA and protein levels. GATA-3 deficient cells generated by expressing a GATA-3 shRNA construct were sensitive to apoptosis induced by etoposide and TNF-α. This apoptotic effect could be partly prevented by the co-treatment with exogenous OPG. Our results suggest new approaches to rescue diseases due to GATA-3 deficiency - such as in hypoparathyroidism, sensorineural deafness, and renal (HDR) syndrome - by OPG therapy.
authors.affiliation: Eaton Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary.
authors.forename: Shyan-Yuan
authors.initials: SY
authors.lastname: Kao
authors.affiliation: 1] Eaton Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary [2] Department of Otology and Laryngology, and Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Konstantina M
authors.initials: KM
authors.lastname: Stankovic
mesh_terms: D050990:GATA3 Transcription Factor / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D053244:Osteoprotegerin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation
chemical_list: D050990:GATA3 Transcription Factor; D053244:Osteoprotegerin; C506030:TNFRSF11B protein, human