RNA polymerase II transcription complex assembly in nuclear extracts

摘要: In vitro transcription systems based on nuclear extracts of eukaryotic cells continue to be valuable experimental for assessing function promoter sequences and defining new activities involved in complex assembly activity, but many aspects such have not been experimentally examined. Here, the from long terminal repeat mouse mammary tumor virus was assessed with a system derived cultured HeLa cells. The extent preinitiation limited by availability template, even though only small fraction template present assays participated transcription. These results support model which DNA has two alternative fates, one leading functional complex, another that leads irreversible inactivation. observed kinetics reflects loss both pathways is dominated relatively rapid rate Supplementing purified TATA binding protein increased as well apparent assembly. Both effects can explained protein-dependent increase altered partitioning between competing pathways.