Lec 6: Epigenetic Gene Regulation

Question 1

What is epigenetic control?

Answer 1

Heritable changes in gene expression that does not involve changes in DNA nucleotide sequence

Question 2

What is genomic imprinting?

Answer 2

Nonequivalence in expression of alleles between the paternal and maternal genomes at certain loci

Question 3

What is different about an imprinted gene?

Answer 3

Only the paternal or maternal allele is expressed in the relevant tissue (most genes are expressed from both maternal and paternal)

Question 4

A gene that is maternally imprinted is expressed only from the ____ allele.
A gene that is paternally imprinted is expressed only from the ____ allele.

Answer 4

Maternally imprinted means only expressed from paternal allele
Paternally imprinted means only expressed from maternal allele

Question 5

At which nucleotide is DNA methylated? Is the DNA more or less available for expression?

Answer 5

At C (cytosine) nucleotides within a CpG sequence
Represses gene expression

Question 6

What enzyme methylates DNA at the CpG site?

Answer 6

Cytosine methyltransferases

Question 7

What helps transmit methylation to daughter cells?

Answer 7

Maintenance methylation carried out by Dnmt1 methyltransferase

Question 8

What mechanism is responsible for methylating genomes in sperm and egg?

Answer 8

De novo methylation