Staudinger Blue boxes

Question 1

Describe how nucleoside analogue inhibitors are able to inhibit DNA synthesis

Answer 1

The nucleoside analogues lack the 3’ OH group allowing them to act as drugs that inhibit DNA synthesis AFTER they are converted to dNTPs and are able to inhibit the DNA polymerase

Question 2

Describe ara-c as an inhibitor of DNA replication

Answer 2

ara-c has a sugar arabinose and is converted into ara-CTP which is a competitive inhibitor of DNA polymerase

used to treat leukemia

Question 3

Describe how AZT is used to treat HIV

Answer 3

The drug is taken up into the HIV cells and is used by the reverse transcriptase

because it also lacks the 3’ OH, it arrests viral synthesis by acting as a chain terminator

Question 4

Describe acyclovir

Answer 4

Used as an anti-viral as it lacks the 3’OH group and acts a DNA chain terminator, stopping synthesis of the DNA

In herpes, the acyclovir is a target of the thymidine kinase that is then able to convert monophosphate into triphosphate?

(I dont super get this pg 324 panini)

Question 5

Describe Xeroderma pigmentosum

Answer 5

Deficiency in the proteins that are involved in the Nucleotide excision repair mechanism, that is involved in repairing UV damage that is done to the body

prone to carcinomas and melanomas secondary to increased cyclobutane thymidine dimers

Question 6

Describe hereditary nonpolyposis colorectal cancers

Answer 6

Due to a mutation of the proteins that are involved in the MER pathway, specifically affecting MSH2, and MLH1

An acquired mutation in the good copy of the gene will lead to an increased risk of tumor development as the MER would be non-functional

Question 7

Describe Cockayne syndrome

Answer 7

autosomal recessive disease that results in mutations of the ERCC-6 (type B-most common) and ERCC-8(type A) genes, which are two of the pivotal pieces in the transcription coupled repair mechanisms. The RNA polymerase stalls over the site of the DNA but the proteins that recognize the damage (ERCC proteins) are not able to relay the message, leading to neurological delays, photosensitivity, and hearing loss or vision issues

Question 8

Describe the BRCA mutations and breast cancer/

What kinds of genes are these?

What DNA repair pathway do they relate to?

Answer 8

The BRCA genes are tumor suppressor genes

BRCA1 also leads to an increased risk of cervical, uterine, pancreatic, and colon cancer AND pancreatic, testicular, and early prostatic cancer in men

BRCA increases the risk of melanoma, pancreatic, stomach, and gallbladder cancers

The BRCA genes are directly associated with the homologous recombination pathways