The chicken c-erbA α-product induces expression of thyroid hormone-responsive genes in 3,5,3′-triiodothyronine receptor-deficient rat hepatoma cells

Abstract

To determine the capacity of the chicken c-erbA (cTR-α) gene product in regulating expression of known thyroid hormone-responsive genes, both the cTR-α and the viral v-erb A genes were expressed in FAO cells, a rat hepatoma cell line defective for functional thyroid hormone receptors. Upon nuclear expression of the cTR-α protein the cells become responsive to thyroid hormone, as detected by expression of a number of genes (malic enzyme, phosphoenolpyruvate carboxykinase, and Na+/K+-ATPase) reported to be indirectly induced by the hormone in vivo. In addition, our data show that the c-erbA product directly activates the Moloney murine leukemia virus promoter in a ligand-dependent manner. The data show that the chicken c-erbA-α protein can modulate the expression of rat genes under either direct or indirect control by thyroid hormone.