Question 1

Which of the following consequences was associated with use of retroviruses in gene therapy of SCID?&#10;A) Short half-life for the vector&#10;B) Dangerous immune response to the vector&#10;C) Insertional mutagenesis&#10;D) The protein product was not expressed in the appropriate location&#10;E) Sufficient levels of the protein product were not achieved

Accepted Answer

The use of retroviruses in gene therapy for SCID resulted in insertional mutagenesis, where the vector integrated into a location in the genome that disrupted normal gene expression and led to the development of leukemia in some patients.

Question 2

According to our current understanding,what makes embryonic stem cells unique compared to other stem cells?&#10;A) They can be engineered to express exogenous DNA&#10;B) Larger DNA segments can be expressed in them&#10;C) They are not rejected by the immune system&#10;D) They can differentiate into any cell type&#10;E) If injected into the bloodstream, they will home to the appropriate location in the body

Accepted Answer

Embryonic stem cells have the unique ability to differentiate into any cell type in the body. This is known as pluripotency, which is not found in other types of stem cells.

Question 3

How might antisense oligonucleotides be used to alleviate the severity of Duchenne muscular dystrophy?&#10;A) By causing the degradation of mutant transcripts&#10;B) By upregulating the expression of the mutant gene&#10;C) By blocking the transcription of the mutant gene&#10;D) By replacing the mutant sequence&#10;E) By blocking exon splice enhancers so that the exon containing the mutation is skipped

Accepted Answer

Antisense oligonucleotides can be used to block exon splice enhancers, which ultimately results in the exon containing the mutation being skipped during transcription. This can lead to a functional dystrophin protein being produced, which can alleviate the severity of Duchenne muscular dystrophy. A, B, C, and D are not viable options since degrading the mutant transcripts, upregulating the mutant gene expression, blocking the transcription of the mutant gene, and replacing the mutant sequence would not address the core issue of the mutation affecting the exon sequence.

Deck 23: Treatment of Genetic Disease