Section IB

Question 1

What is the basis of somatic cell therapy?

Answer 1

-involves the alterations in human somatic cells to treat aspecific disorder

Question 2

What cells meet the requirements for proliferating cells as well as long life in somatic cell therapy?

Answer 2

-Bone marrow stem cells

Question 3

What are some methods of Gene replacement therapy?

Answer 3

• retroviral vectors
• adenoviral vectors
• adeno associated viral vectors (AAV)
• lentiviral vectors

Question 4

What are the qualities of a retroviral vector?

Answer 4

• only effective against actively dividing cells (good or bad)
• could activate proto-oncogenes (cause cancer)

Question 5

What are some qualities of the adenoviral vectors?

Answer 5

• dsDNA virsu that can transduce non-dividing cells
• des not integrate to it is eventually deactivated
• produces an immune response

Question 6

What are characteristics of the adeno-associated viral vectors (AAVs)

Answer 6

• low immune response
• long acting
• low capacity

Question 7

What are the characteristics of a lentiviral vector? What is a well known lentivirus?

Answer 7

• HIV is a lentivirus
• can transduce non-dividing cells
• larger inserts (8kb)
• current focus of research.

Question 8

What are the non-viral vectors?

Answer 8

• liposomal vectors
• whole synthetic human cheomosomes

Question 9

What is the prupose and kinds of gene-blocking therapies?

Answer 9

• Used to treat a gain-of-function mutation
• Antisense therapy
• Ribozyme therapy
• RNA interference

Question 10

What is the throy behind an antisense therapy?

Answer 10

• an oligonucleotide with an antisense mutation is inserted into the over translated region.
• problems:

–>often degraded before target acqusistion

–>small variations in host sequence can disable the therapy binding

Question 11

What is the theory behind the gene-blocking technique of ribozyme therapy?

Answer 11

-Enzymes that are engineered against certain mRNA sequences and destry them before they can be translated

Question 12

How does RNAi work? What are its pros and cons?

Answer 12

• RNAi works through the enzyme Dicer which chops up viral dsRNA.
• These small peices are then used to recognize any ssRNA floating around.
• The dsRNA can be engineered for the target sequence and used to destry the mRNA in question.