Rapid Communication: A cis-Acting Element, Tα-1, in the Upstream Region of Rod α-Transducin Gene that Binds a Developmentally Regulated Retina-Specific Nuclear Factor

Abstract: The G protein transducin (T) is an integral component of the signal transduction pathway in photoreceptors. We have identified a cis -acting element, Ta-1, in the upstream region of the mouse rod a-T (T_rα) gene that may be important for tissue-specific expression. Tα-1 binds a retina-specific nuclear factor of apparent molecular mass of 90 kDa. Binding to the Tα-1 site is developmentally regulated and peaks between postnatal days 6 and 9. This corresponds to the time of rod photoreceptor maturation and the rise in T_rα gene expression. The sequence of Tα-1 shows homology with RET-1, a cis -acting element in the proximal promoter of opsin gene that binds a distinct retina-specific factor. Tα-1 and RET-1 sequences may have been derived from a prototype Tα-1/RET-1 sequence, evolved to confer photoreceptor specificity on retina-specific genes.