ORDERED ASSEMBLY OF A FUNCTIONAL PREINITIATION TRANSCRIPTION COMPLEX,CONTAINING VACCINIA VIRUS EARLY TRANSCRIPTION FACTOR AND RNA-POLYMERASE, ON AN IMMOBILIZED TEMPLATE

A functional preinitiation transcription complex was formed by incubat ing vaccinia virus early transcription factor VETF and RAP94(+) RNA po lymerase with an early promoter template immobilized on paramagnetic p articles. A preferred order of assembly, VETF followed by RNA polymera se, was demonstrated by stepwise addition experiments. ATP was unneces sary for preinitiation transcription complex formation, but divalent c ations were required specifically for the association of RNA polymeras e.