Question

Which of the following is true about histone acetyltransferase (HAT)?

A) HATs have an overall effect of increasing the positive charges on DNA.
B) HATs will make the chromatin more compacted and less available to transcription regulatory proteins.
C) HATs will remove acetyl groups from histone proteins.
D) HATs are usually linked to increasing gene expression.
E) HATs will add acetyl groups to DNA.

Answer 1

HATs, or histone acetyltransferases, are linked to increasing gene expression by adding acetyl groups to histone proteins, which reduces the positive charge on the histones and allows for a more open chromatin structure accessible to the transcription machinery.

Step-by-step explanation:

The correct answer is: D) HATs are usually linked to increasing gene expression.

Histone acetyltransferases (HATs) are enzymes that play a crucial role in the regulation of gene transcription by modifying histones, the proteins around which DNA is wrapped. The addition of acetyl groups to histone proteins by HATs reduces the positive charge on the histones, leading to a looser association with the negatively charged DNA. This reduced binding allows chromatin to adopt a more open conformation, making it easier for transcription machinery, including transcription factors and RNA polymerase, to access the DNA and initiate transcription.

By contrast, the other options A, B, C, and E do not accurately describe the role of HATs. Specifically, HATs do not increase the positive charges on DNA or make chromatin more compact; they do not remove acetyl groups from histone proteins (that is the role of histone deacetylases); and they do not add acetyl groups to DNA.