What happens to chromatin when histone acetyltransferases (HATs) are active?

What happens to chromatin when histone acetyltransferases (HATs) are active?

• A. Chromatin becomes more compacted
• B. Transcription is inhibited
• C. DNA becomes more accessible for transcription
• D. Histones become deacetylated

Answer: (C)

When histone acetyltransferases (HATs) are active, they add acetyl groups to the lysine residues on histone proteins. This process leads to a more relaxed and open chromatin structure, which is often referred to as euchromatin. The addition of acetyl groups neutralizes the positive charge on the histones, reducing the interaction between the histones and the negatively charged DNA. As a result, the chromatin becomes less compacted, allowing transcriptional machinery, such as RNA polymerase and transcription factors, easier access to the DNA. This increased accessibility facilitates the process of transcription, enabling genes to be expressed more readily. In summary, the activity of HATs modifies histones in a way that promotes a more open chromatin state, enhancing the accessibility of DNA for transcription. This is why the option stating that DNA becomes more accessible for transcription is the correct answer.

When histone acetyltransferases (HATs) are active, they add acetyl groups to the lysine residues on histone proteins. This process leads to a more relaxed and open chromatin structure, which is often referred to as euchromatin.

The addition of acetyl groups neutralizes the positive charge on the histones, reducing the interaction between the histones and the negatively charged DNA. As a result, the chromatin becomes less compacted, allowing transcriptional machinery, such as RNA polymerase and transcription factors, easier access to the DNA. This increased accessibility facilitates the process of transcription, enabling genes to be expressed more readily.

In summary, the activity of HATs modifies histones in a way that promotes a more open chromatin state, enhancing the accessibility of DNA for transcription. This is why the option stating that DNA becomes more accessible for transcription is the correct answer.