Increased activity of HAT leads to what change in transcription?

The correct answer highlights the role of histone acetyltransferases (HAT) in modifying chromatin structure and its implications for transcription. HATs add acetyl groups to lysine residues on histone proteins, resulting in a change in the charge of the histones. Specifically, lysine is positively charged at physiological pH, and the addition of an acetyl group neutralizes this positive charge, thereby reducing the overall positive charge of the histones.

This reduction in positive charge leads to a more relaxed chromatin structure, which facilitates access for transcription factors and RNA polymerase to the DNA template. Consequently, the transcription of certain genes is enhanced as the chromatin becomes more accessible for the transcription machinery. This underlines the importance of HAT activity in promoting gene expression by altering the ionic nature of histones and enabling a more open and transcriptionally active chromatin state.

The other options do not accurately capture the role of HATs; they either imply negative effects on transcription or incorrect changes in charge state. Thus, the reference to increased positive charge directly aligns with the biochemical action of HATs and their functional implications for transcription regulation.