Gene Regulation

Question 1

What are the five major levels of gene regulation?

Answer 1

1.) Epigenetic
2.) Transcriptional
3.) RNA processing
4.) Translational
5.) Post-translational

Question 2

What epigenetic mechanisms turn genes ON/OFF?

Answer 2

DNA methylation → OFF
Histone acetylation → ON
Chromatin remodeling complexes adjust accessibility

Question 3

What is combinatorial control?

Answer 3

Different combinations of transcription factors regulate distinct gene expression patterns → defines cell identity

Question 4

What is alternative splicing?

Answer 4

A single gene produces multiple mRNA isoforms by selecting different exon combinations

Question 5

What does ubiquitination do?

Answer 5

Tags proteins for degradation by the proteasome

Question 6

What does phosphorylation do as a post-translational modification?

Answer 6

Alters protein activity, conformation, or localization (“on/off switch”)

Question 7

Why do different cell types express different genes if they all contain the same DNA?

Answer 7

They express different transcription factors and have unique epigenetic landscapes

Question 8

List five mechanisms of eukaryotic gene regulation

Answer 8

Chromatin modification, transcriptional control, post-transcriptional control, translational control, post-translational control

Question 9

Give an example of chromatin-level regulation

Answer 9

Histone acetylation increasing transcription

Question 10

Give an example of post-transcriptional regulation

Answer 10

Alternative splicing

Question 11

What is an enhancer?

Answer 11

A DNA sequence that increases transcription when bound by activator TFs

Question 12

Define silencer

Answer 12

A DNA element that represses transcription via binding to repressors

Question 13

What is a histone?

Answer 13

Protein that DNA wraps around to form nucleosomes

Question 14

What is alternative splicing?

Answer 14

Producing multiple mRNA isoforms from one gene

Question 15

How do TFs regulate genes combinatorially?

Answer 15

Multiple TFs bind together to integrate signals and activate or repress transcription

Question 16

What does strong reporter expression indicate?

Answer 16

The regulatory element is active in that tissue/cell type

Question 17

What does loss of reporter signal after mutating an enhancer mean?

Answer 17

The mutated region contains important TF binding sites