What is required for the transition from initiation to elongation in transcription?

The transition from initiation to elongation in transcription is critically dependent on modifications to RNA polymerase II (RNAP2). During the initiation phase, transcription factors and RNA polymerase II assemble at the promoter to form a transcription initiation complex. Once the transcription bubble is formed and RNA synthesis begins, specific post-translational modifications of RNAP2, particularly phosphorylation of the C-terminal domain (CTD), play a significant role in facilitating the transition to elongation.

Phosphorylation of the CTD enables RNA polymerase II to move away from the promoter, effectively transitioning into the elongation phase where RNA synthesis continues. These modifications are essential as they help in recruiting additional factors that assist in elongation and processing of the nascent RNA transcript.

The other choices do not directly facilitate this transition. For example, the release of general transcription factors, while important for the initiation phase, occurs at the end of initiation but does not directly affect the transition to elongation. Consolidation of transcription factors is more related to the stability of the initiation complex rather than the transition itself. Degradation of RNA precursors does not play a role in the transition between initiation and elongation; instead, it is more related to RNA quality control and regulation post-transcription