In gel shift analyses, PAX8-PPARgamma bound a PPARgamma-response element suggesting that its transcriptional function is mediated via direct DNA contact.     ///    This study investigated the transcriptional mechanisms by which PAX8-PPARgamma regulates follicular thyroid cells.     ///    PAX8-peroxisome proliferator-activated receptor gamma (PPARgamma) disrupts normal PAX8 or PPARgamma transcriptional function and stimulates follicular thyroid cell growth..     ///    "In HeLa cells, rat follicular thyroid (FRTL-5) cells, or immortalized human thyroid cells, PAX8-PPARgamma stimulated transcription from PAX8-responsive thyroperoxidase and sodium-iodide symporter promoters in a manner at least comparable with wild-type PAX8. "    ///    "Therefore, PAX8-PPARgamma disrupts normal transcriptional regulation by stimulating some genes and inhibiting others, the net effect of which may mediate follicular thyroid cell growth and loss of differentiation that ultimately leads to carcinogenesis.. "    ///    "Unexpectedly, PAX8-PPARgamma transcriptional function on a PPARgamma-responsive promoter was cell-type dependent. "    ///    "In contrast, PAX8-PPARgamma failed to stimulate transcription from the thyroglobulin promoter and blocked the synergistic stimulation of this promoter by wild-type PAX8 and thyroid transcription factor-1. "    ///    "In this model, PAX8-PPARgamma expression was associated with enhanced growth as assessed by soft agar assays and thymidine uptake. "    ///    "in HeLa cells, PAX8-PPARgamma dominantly inhibited expression of the PPARgamma-responsive promoter, whereas in FRTL-5 and immortalized human thyroid cells PAX8-PPARgamma stimulated this promoter. "    ///    A biological model of PAX8-PPARgamma function in follicular thyroid cells was generated via constitutive expression of the fusion protein in FRTL-5 cells. 