Final answer:
The +1 nucleosome has modified histone proteins, which affect nucleosome spacing and gene expression by making DNA accessible for transcription when spaced apart.
Step-by-step explanation:
The +1 nucleosome has a modified histone protein. These modifications, such as methylation or acetylation of histone tails, play a crucial role in regulating gene expression. These chemical changes can alter the spacing between nucleosomes, making the DNA accessible and allowing gene activation.
When nucleosomes are closely packed, transcription factors cannot bind, which turns gene expression off. Conversely, when nucleosomes are spaced further apart, DNA becomes more exposed, enabling transcription factors to bind and activate gene expression. Essentially, the modification of histones affects the physical structure of the chromatin, influencing the accessibility of the genes and the ability to be transcribed.
The +1 nucleosome has a modified histone tail. This modification allows for changes in nucleosome spacing and can affect gene expression. It can either enhance or repress gene activity, depending on the specific modification. For example, acetylation of the histone tail in the +1 nucleosome can lead to increased transcription and gene activation.