Final answer:
Histone H1 is released during chromatin remodeling, which allows for the DNA to become accessible for transcription. This involves chemical modifications such as histone acetylation and processes like the FACT complex that facilitate the transcription machinery's access to DNA.
Step-by-step explanation:
Chromatin Accessibility and Histone Release
Histone H1 is released from chromatin through a process called chromatin remodeling. This process is essential for regulating gene transcription and involves the chemical modification of histone proteins, such as acetylation, methylation, and phosphorylation. Acetylation of histones, for instance, tends to unwind the nucleosomes making the underlying DNA accessible for transcription. The FACT protein complex also plays a crucial role in chromatin remodeling during transcription. It facilitates the removal of histones from DNA to allow for the RNA polymerase to synthesize pre-mRNA and then repositions the histones after transcription has occurred.
Additionally, specific extractions, like acidic or salt extractions, can dissociate histones and other proteins from chromatin, as demonstrated by experiments. The level of chromatin condensation changes during the cell cycle, with chromosomes being the most condensed form during mitosis. During interphase, active genes are found in a less condensed form known as euchromatin, which allows easier access for transcription machinery.