Chapter 3 Self-check questions

. Which experimental method is not used to study transcription factor binding?

Gel/band shift assays

DNAse footprinting.

Sodium bisulphate treatment and methylation specific PCR

Promoter mutagenesis and in vitro transcription assays.

. Which one of the following is false?

Hypermethylation of promoter regions activates gene expression.

Epigenetic alterations do not cause mutation.

Epigenetic alterations regulate gene expression.

Histone acetyltransferases (HATs) acetylate specific histone-tail lysine amino acids and this correlates with increased gene expression.

. Which of the following therapeutic strategies is incorrectly matched to a drug for cancer treatment?

DNA methylation inhibitor: 5-aza-2'-deoxycytidine

Telomerase inhibitor: Imetelstat

HAT (histoine acetyltransferase) inhibitors: SAHA (vorinostat)

HDAC (histone deacetylase) inhibitors: Romidepsin

. Which one of the following statements is false?

AP-1 is a transcription factor which is important for cellular growth, differentiation and death.

AP-1 binds to the TPA response element in the promoter region of their target genes.

AP-1 is made of one component from either the Jun family or the Fos family.

AP-1 is activated in response to specific signals such as growth factors, ROS and radiation.

. Which one of the following enzymes is not associated with epigenetic carcinogenesis?

DNA methyltransferase.

Telomerase.

DNA polymerase δ/ε

Histone acetyltransferase.

. Which statement below about is false?

Telomeres can be transcribed into long noncoding RNA that contains telomeric repeat-containing RNA which can inhibit telomerase.

Telomeres protect the ends of chromosomes from digestion by nucleases.

Telomere length is maintained in some cells by an enzyme that contains reverse transcriptase activity and an RNA template.

Telomeres induce mechanisms that repair DNA double-strand breaks.

. Which one of the following statements is false?

Telomeres shorten with each round of replication.

Telomeres are composed of thousands of TTAGGG repeats and their associated shelterin complex.

Telomeres play a role in the replicative potential of a cell.

Telomerase activity is decreased in 90% of tumors.

. The majority of cancer-related single nucleotide polymorphisms are located in:

Coding regions of the genome

Introns and exons

Untranslated regions and coding regions

Intergenic (between genes) and introns of the genome

. What is the role of histone acetyltransferases (HATs) in epigenetic regulation of transcription?

They remove acetyl groups from histones.

They increase chromatin folding by adding acetyl groups.

They add acetyl groups to histones and relax chromatin folding.

They restore a positive charge to lysine residues of the histone tails and increase chromatin compaction.

. Which statement about microRNAs (miRNAs) is false?

They are small non-protein–coding RNAs that are processed into a mature single-stranded molecule that joins with an RNA-induced silencing complex (RISC).

They hybridize to the 5' end of a specific mRNA and block the initiation of translation.

It has been demonstrated that overexpression of a single miRNA, called mir-155, can lead to cancer in mice.

miRNA expression profiles of tumors are able to discriminate between different types of cancer

. A non-invasive DNA stool test used for screening for colorectal cancer includes the examination of which of the following epigenetic markers?

Histone acetylation

Histone deacetylation

Promoter methylation of specific gene promoters

Non-coding RNAs

. Which is true about the relationship between the epigenome and mutation?

Areas of open chromatin are associated with low mutation density.

Areas of open chromatin are associated with high mutation density.

Areas of methylation are associated with deletions

Areas of methylation are associated with DNA base pair insertions.

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