The poly(A) signal, without the assistance of any downstream element, directs RNA polymerase II to pause in vivo and then to release stochastically from the template.

摘要: Genes encoding polyadenylated mRNAs depend on their poly(A) signals for termination of transcription. Typically, transcription downstream the signal gradually declines to zero, but often there is a transient increase in polymerase density immediately preceding decline. Special elements called pause sites are traditionally invoked account this increase. Using run-on from nuclei transfected cells, we show that both and gradual decline follow site generated entirely by itself series model constructs. We found no other be involved argue do not function through pausing. Both poly(A)-dependent subsequent occurred earlier stronger than weaker one. Because resembles abortive elongation occurs many promoters, one has proposed flips mode like binary switch. compared elongators with terminators 4-fold difference processivity. conclude terminating polymerases merely revert prior state low processivity rather convert new termination-prone condition.