PHOSPHORYLATION OF THE N-TERMINAL DOMAIN OF XENOPUS TATA-BOX BINDING-PROTEIN BY DNA-DEPENDENT PROTEIN-KINASE DEPENDS ON THE C-TERMINAL COREDOMAIN

DNA-dependent protein kinase (DNA-PK) has been shown to phosphorylate several transcription factors in vitro, suggesting that this nuclear e nzyme - in addition to its role in DNA repair and recombination - may be involved in transcriptional regulation. In the typical mechanism th e DNA-bound kinase phosphorylates a substrate that is bound to the sam e DNA molecule. Here I report that the Xenopus TATA-box binding protei n (xTBP) is hyperphosphorylated by DIVA-PK in vitro. The phosphorylati on is in the N-terminal domain of the protein but depends fully on the presence of the C-terminal core domain.