The promoter of the H1zero histone gene contains a DNA element bound by retinoic acid receptors.

Retinoic-acid mediated differentiation of F9 cells is accompanied by an increased transcription of the histone H1zero gene. This increase is an early response after addition of retinoic acid, suggesting a direct effect of the hormone on transcription of the gene. We show now that the promoter of histone H1zero contains a DNA element, localized 531 base-pairs upstream of the cap site, that is composed of a direct repeat of the sequence PuGGTCA separated by eight base-pairs. This element confers retinoic acid responsiveness to a heterologous thymidine kinase promoter in F9 and HeLa cells. Furthermore, the element forms retarded complexes not only with bacterially expressed retinoic acid receptors (RARs) and retinoid X receptors (RXRs), but also with endogenous F9 receptors. Our results suggest therefore that retinoic acid receptors can control the expression of a chromatin structural gene the expression of which is associated with a differentiated phenotype.