Abstract
The nature of the cyclic[c]AMP-receptor-nucleus interactions was examined by a novel combination of 2 photoreactions. A photosensitive derivative of cAMP, N6-butyryl cAMP, was covalently attached to its cytoplasmic receptod by photo-affinity labeling and this receptor complex was photo-crosslinked by the DNA in the rat liver nuclei. The photolytic reactions seemed to be specific since stable links were formed only when substantial noncovalent binding occurred.