REQUIREMENT OF CASEIN KINASE-II-MEDIATED PHOSPHORYLATION FOR THE TRANSCRIPTIONAL ACTIVITY OF HUMAN RESPIRATORY SYNCYTIAL VIRAL PHOSPHOPROTEIN-P - TRANSDOMINANT NEGATIVE PHENOTYPE OF PHOSPHORYLATION-DEFECTIVE P-MUTANTS

The transcription complex of the human respiratory syncytial virus was biochemically dissected and reconstituted in vitro with purified vira l macromolecules. The minimal complex consisted of the viral N-RNA tem plate, viral phosphoprotein (P), and the large protein (L) along with host cellular factor(s), possibly actin. Active transcription could al so be reconstituted using bacterially synthesized recombinant P protei n provided the P protein was phosphorylated by cellular casein kinase II, Elimination of phosphorylation by inhibition of CKII or by mutatio n of the Ser residue at position 237 of the P protein also abrogated R SV transcription. In addition, the phosphorylation-defective P mutants exhibited a trans-dominant negative phenotype, consistent with the fi nding that the mutant proteins bound to the N-RNA template as efficien tly as the wild type. Once engaged in transcription, however, the wild -type P protein became refractory to trans-inhibition by the mutant. ( C) 1994 Academic Press, Inc.