Lecture G12 (Gene Expression)

What is gene expression?

The process of using DNA information to produce proteins or function RNAs

What is differential gene expression?

Different genes are expressed in different cells despite having the same genome

What is the most common stage where eukaryotic gene regulation occurs?

Transcription

What stage precedes transcription and influences whether genes can be accessed?

Chromatin modification

How does chromatin structure affect transcription?

Looser chromatin promotes transcription; tighter chromatin inhibits it

What does histone acetylation do?

Loosens chromatin → increases transcription

What does DNA methylation do?

Reduces transcription and can silence genes long-term

What are general transcription factors?

Proteins required for transcription of all protein-coding genes

What are control elements?

DNA sequences that transcription factors bind to regulate transcription

What are enhancers?

Distal control elements that increase transcription when activators bind

What is the role of activators?

Bind enhancers and stimulate transcription

What is the role of repressors?

Block activators or alter chromatin to inhibit transcription

What is epigenetics?

Heritable gene expression changes not caused by changes in DNA sequence

What is DNA methylation best known for in development?

Genomic imprinting—parent-of-origin-specific gene expression

How can identical twins differ in disease risk?

Different epigenetic modifications