(1). How are nucleosomes disassembled to allow transcription and then reassembled? According to our textbook, Life: The Science of Biology , one way to regulate the expression of genes is through changing the chromatin structure. Recall that nuclear proteins, histones, are responsible for tightly packaging DNA into nucleosomes. When this occurs, the initation and elongation processes in transcriptions are blocked. According to Molecular Biology of the Cell , Alberts and colleagues noted in their textbook that the purpose of this was to prevent “leaky transcription.” Thus, to overcome these two blockages, chromatin remodeling will occur. As an overview, in initiation, a remodeling protein will bind upstream of the initation site, and will disaggregate the nucleosome. This will allow the transcription complex to bind, and RNA polymerase can begin transcription. Meanwhile, in elongation, a second remodeling protein can bind to the nucleosome, which allows transcription without disaggregation. The transcription
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