Lecture 8: DNA replication, repair and disease

Question 1

Short telomere syndrome (STS) definition, cause, what cells affected

Answer 1

Accelerated aging syndromes
Caused by gene mutations causing decreased telomere length
Affects organs with high cell turnover

Question 2

Enzyme/process affected in Xeroderma pigmentosum

Answer 2

UV light causes pyrimidine dimers, NER defect

Skin cancer, UV sensitivity, neurological abnormalities

Question 3

Enzyme/process affected in Ataxia telangiectasia (AT), type of inheritance, phenotype

Answer 3

ATM protein (a protein activated by double-strand breaks)
Autosomal recessive
Leukemia, lymphoma, genome instability

Question 4

Enzyme/process affected in Bloom syndrome, phenotype

Answer 4

DNA helicase (RecQ) needed for recombination
Cancer at several sites, stunted growth, genome instability

Question 5

Thymine dimers caused by, affect on cell, repaired by

Answer 5

UV light causes covalent bond between thymines
Block replication and kill cell
NER

Question 6

ATM

Answer 6

Kinase that responds to DNA damage by phosphorylating key substrates involved in DNA repair

Question 7

How do RecQ helicases protect from cancer

Answer 7

They seem to maintain genomic stability by function at the interface between DNA replication and repair

Question 8

What is BLM

Answer 8

RecQ helicase family member, which when defective, can give rise to cancer predisposition disorders such as Blooms syndrome

Question 9

RecQ family members include

Answer 9

BLM, WRN, RecQ4

Question 10

What type of mutation is typically found in BLM or WRN genes

Answer 10

Trucation mutations

Question 11

How is BLM related to BRCA1 and BRCA2

Answer 11

BLM is part of the BRCA1 complex and directly interacts with RAD51