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Multiple Choice
Which of the following would probably not increase the accessibility of DNA for gene transcription?
A
Chromatin remodeling
B
Histone removal
C
Methylation of DNA
D
Acetylation of histone proteins
Verified step by step guidance
1
Understand that gene transcription requires DNA to be accessible to transcription machinery. This accessibility is influenced by the structure of chromatin, which is DNA wrapped around histone proteins.
Chromatin remodeling involves the repositioning or restructuring of nucleosomes (DNA-histone complexes) to make DNA more accessible for transcription. This process generally increases accessibility.
Histone removal refers to the removal of histone proteins from DNA, which would directly increase the accessibility of DNA for transcription by reducing the physical barriers.
Acetylation of histone proteins involves the addition of acetyl groups to histones, which reduces the positive charge on histones, decreasing their affinity for negatively charged DNA. This process generally increases DNA accessibility.
Methylation of DNA typically involves the addition of methyl groups to the DNA molecule, often leading to a more compact chromatin structure and reduced accessibility for transcription. Therefore, methylation of DNA would probably not increase the accessibility of DNA for gene transcription.