What role does FACT play in eukaryotic transcription?

FACT, or Facilitates Chromatin Transcription, is a crucial protein complex involved in the regulation of eukaryotic transcription. It plays a significant role in enabling the transcription machinery to access DNA within chromatin, which is a highly compacted form of DNA that is associated with histones.

The correct choice highlights that FACT is involved in dismantling histones during transcription. As RNA polymerase moves along the DNA to synthesize RNA, it encounters nucleosomes—structures consisting of DNA wrapped around histone proteins. The presence of these histones can impede the progress of RNA polymerase, making it difficult for the transcription machinery to effectively transcribe genes.

FACT acts by binding to nucleosomes and promoting the disassembly of histones, thereby allowing RNA polymerase to traverse through the chromatin more freely. Once the transcription process is complete, FACT can also help in reassembling the histones to restore the chromatin structure. This dual function underscores the importance of FACT in maintaining the balance between transcriptional activity and chromatin organization.

Other choices do not accurately describe the role of FACT in eukaryotic transcription. For instance, although ribosome binding is a critical aspect of protein synthesis, it is not within FACT's purview. mRNA