Genome and Epigenome

Question 1

5 major classes of functional non-coding DNA

Answer 1

1. Promoter and enhancer regions
2. Binding sites for chromatin organising factors
3. Non-coding regulatory RNAs
4. Mobile genetic elements
5. Structural elements eg telomeres and centromeres

Question 2

2 most common forms of genetic variation

Answer 2

1. Single nucleotide polymorphisms (SNPs)

2. Copy number variations (CNVs)

Question 3

What do miRNAs do?

Answer 3

Post-transcriptional silencing

Question 4

Roles of lncRNA

Answer 4

1. Gene activation - facilitate transcription factor binding
2. Gene suppression - act as decoy for transcription factor
3. Altered histone and DNA methylation and acetylation
4. Provide structural scaffolding for secondary/tertiary structures and multisubunit complexes that influence chromatin architecture or gene activity

Question 5

List the different kinds of histone regulatory proteins

Answer 5

1. Chromatin remodelling complex - repositions nucleosomes
2. Chromatin writers - apply marks
3. Chromatin erasers - remove marks
4. Chromatin readers - bind marks

Question 6

List 3 epigenetic factors regulating gene expression

Answer 6

1. Histones and histone modifying factors
2. DNA methylation
3. Chromatin organising factors

Question 7

Which histone residues are methylated?

Answer 7

Lysine and arginine - activates or represses

Question 8

Which histone residues are acetylated?

Answer 8

Lysine - activates

Question 9

Which histone residues are phosphorylated?

Answer 9

Serine - activates or represses

Question 10

What does DNA methylation usually do?

Answer 10

Gene silencing

Question 11

Which enzymes control DNA methlation?

Answer 11

1. DNA methyltransferases
2. Demethylating enzymes
3. Methylated-DNA binding proteins

Question 12

What do chromatin organising factors do?

Answer 12

Control long-range looping of DNA, regulating spatial relationship between gene enhancers and promoters.