A complex deoxyribonucleic acid response element in the rat Ca2+/calmodulin-dependent protein kinase IV gene 5′-flanking region mediates thyroid hormone induction and chicken ovalbumin upstream promoter transcription factor 1 repression

Ca2+/Calmodulin-dependent protein kinase IV (CaMKIV) is regulated by T-3 in a time- and concentration-dependent manner in the developing rat brain and plays an important role in neuronal-specific gene regulation. T-3 treatment, but not retinoic acid (RA), stimulated endogenous CaMKIV mRNA 5-fold in mouse embryonic stem (ES) cells differentiated into neurons. We localized a region -750 to -700 in the CaMKIV gene 5'-flanking region that conferred T-3 responsiveness and bound thyroid hormone receptor (TR), retinoic acid receptor (RAR), and chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1). T-3 and RA treatment stimulated the CaMKIV hormone response element. Cotransfection of a COUP-TF1 expression vector repressed the T-3 response and augmented the RA response. Mutational analysis identified three half-sites arranged in a direct repeat (AB) and overlapping inverted repeat (BC), required for functional induction and receptor binding. TR and RAR bound predominantly to the BC portion of the element and COUP-TF1 to the AB region, with a close correlation of binding and functional studies. COUP-TF1 binding did not influence TR/retinoid X receptor binding but modestly augmented RAR/retinoid X receptor binding. A single element confers T-3 and COUP-TF1 regulation of CaMKIV expression.