What is the purpose of chromatin remodeling in gene regulation?

• A. To alter nucleosome positioning to allow access for transcription machinery
• B. To degrade DNA
• C. To export mRNA
• D. To encode tRNA

Answer: (A)

DNA in chromatin is wrapped around histones, forming nucleosomes that can block access to genes. Chromatin remodeling uses energy to reposition, eject, or restructure these nucleosomes, changing how tightly DNA is packaged at specific regions. By moving nucleosomes away from promoter and enhancer areas, the DNA becomes accessible to transcription factors and RNA polymerase II, allowing transcription to start. Conversely, repositioning nucleosomes over regulatory regions can hide them and repress transcription. So the main purpose is to alter nucleosome positioning to permit access for the transcription machinery. This isn’t about degrading DNA or about exporting mRNA or encoding tRNA, which are separate steps in gene expression.