What is the role of chromatin in transcriptional regulation?

In eukaryotes, the tight or loose packaging of the genes in chromatin (DNA plus specific proteins) can control whether the genes can be expressed to form their encoded product. Chromatin is usually not “permissive” but it can be modified in specific areas to open it up for transcription of the genes.

How is chromatin modification regulated?

The regulation of gene expression within euchromatin requires the delivery of chromatin-modifying enzymes by DNA-bound transcription factors. For the purposes of transcription, modifications can be divided into those that correlate with activation and those that correlate with repression.

What are the mechanisms of transcriptional regulation?

These mechanisms can be generally grouped into three main areas: Control over polymerase access to the gene. This is perhaps the broadest of the three control mechanisms. This includes the functions of histone remodeling enzymes, transcription factors, enhancers and repressors, and many other complexes.

How does chromatin modification affect gene expression?

Chromatin remodeling is the rearrangement of chromatin from a condensed state to a transcriptionally accessible state, allowing transcription factors or other DNA binding proteins to access DNA and control gene expression. Chromatin remodeling is highly implicated in epigenetics.

What is the role of chromatin in transcriptional regulation quizlet?

It modifies nucleosomes and promotes high levels of transcription.

Does chromatin have RNA?

In addition to core histones, higher eukaryotes contain linker histone H1. Here, we report results indicating that RNA plays a general structural role in eukaryotic chromatin. Our results indicate that purified chromatin contains significant amounts of RNA (2%–5% of total nucleic acids).

What chromatin modification is associated with open DNA?

In this open chromatin conformation, called euchromatin, DNA is accessible to binding of transcriptional machinery and subsequent gene activation. In contrast, modifications that strengthen histone-DNA interactions create a tightly packed chromatin structure called heterochromatin.

Where does transcriptional regulation occur?

Prokaryotic transcription and translation occur simultaneously in the cytoplasm, and regulation occurs at the transcriptional level. Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm.

Where does post-transcriptional regulation occur?

Post-transcriptional regulation is the control of gene expression at the RNA level. It occurs once the RNA polymerase has been attached to the gene’s promoter and is synthesizing the nucleotide sequence.

How does modification of histones affect gene expression?

The PTMs made to histones can impact gene expression by altering chromatin structure or recruiting histone modifiers. Histone modifications act in diverse biological processes such as transcriptional activation/inactivation, chromosome packaging, and DNA damage/repair.

At what levels does gene regulation occur in prokaryotes quizlet?

In bacteria, gene expression can be controlled at what three levels? Transcription, translation or post-translation. Negative control occurs when a regulatory protein prevents transcription.