Question

True or false? One possible way to alter chromatin structure such that genes could be transcribed would be to make histone proteins more positively charged.

Answer 1

Answer:

False

Explanation:

The histones that are more positively charged, tight hardly to negatively charged DNA. So, enzymes, such as acetyltransferases, that reduce the positive charge of histones promote transcription.

Chromatin structure and its modifications can change the package of the DNA and consequently, alter the gene expression. The most common modifications of the chromatin are covalent modifications such as acetylation/deacetylation (by acetyltransferases and eacetylases), methylation (by methyltransferases), and phosphorylation (by kinases).  This is the way of gene expression regulation.

The effects of modifications are different, for example methylation promotes  condensation of the chromatin and as a consequence, prevents binding of transcription factors to the DNA (transcription is repressed).

Acetylation loosens the association between nucleosomes and DNA (because it neutralizes the positive charge of histones) and consequently promotes transcription. Deacetylation is a process opposite to acetylation.