In eukaryotes, nucleosome remodelers:

Correct option is C

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Nucleosome remodelers are protein complexes that regulate chromatin structure and facilitate access to DNA for processes such as transcription, replication, and repair. These remodelers modify the structure of nucleosomes by altering the position of histones, thereby affecting the DNA accessibility.

Creating DNase I hypersensitive sites is a function of nucleosome remodelers. DNase I hypersensitive sites refer to regions of chromatin that become more accessible to DNAse I digestion, indicating that the chromatin in these regions is less compact and more open. This typically occurs in regions that are actively transcribed or undergoing other genetic processes.

         Roles of Nucleosome Remodelers:

• They can alter the positioning of nucleosomes, making the DNA more accessible to the transcription machinery.
• While they do not directly acetylate or methylate histones (such actions are typically carried out by other specific enzymes), their role is crucial in maintaining the chromatin structure conducive for gene expression.
• Nucleosome remodelers do not degrade histones but may help reposition them.

Information Booster:

1. Nucleosome remodeling complexes often work in conjunction with histone-modifying enzymes to facilitate transcription.
2. DNase I hypersensitive sites are indicators of active transcription regions and are used as a marker for gene activity.
3. The process of chromatin remodeling involves the use of energy from ATP to move or evict histones from specific regions of DNA.
4. Histone modification (e.g., acetylation or methylation) is carried out by other enzymes such as histone acetyltransferases (HATs) or histone methyltransferases (HMTs).
5. Nucleosome remodelers help in the dynamic regulation of chromatin by providing accessibility to transcription factors and the transcription machinery.

Additional Information :

• Option 1 (Methylate histone H3 - Incorrect): Methylation of histones, particularly histone H3, is carried out by histone methyltransferases and is not a function of nucleosome remodelers.
• Option 2 (Acetylate histone H3 and H4 - Incorrect): Acetylation of histones is carried out by histone acetyltransferases (HATs), not nucleosome remodelers.
• Option 4 (Degrade histone subunits - Incorrect): Nucleosome remodelers do not degrade histones. Their role is to reposition or evict histones, not degrade them.