Download Activity 2.2.1 Student Response Sheet

Response Sheet modified from Genetic Science Learning Center – Gene Therapy: Molecular Bandage?
Activity 2.2.1 Student Response Sheet
Vectors Used In Gene Therapy
Retrovirus
How the vector carries
genetic material
Maximum length of
DNA that can be
inserted with this
vector
In the form of RNA;
most famous is HIV;
affects only dividing
cells
VIRAL
8,000 bp
Adenovirus
DNA (common cold)
Adeno-Associated Virus
ssDNA (do not cause illness
in humans)
VIRAL
VIRAL
7,500 bp
5,000 bp
Advantages of Use
Contains enzyme to
convert RNA to DNA
before genes can be
activated; DNA will
integrate into host
cell’s genome @
random locations; Will
duplicate when the cell
divides
Affect diving & nondividing cells; Once
adenovirus infects cell,
DNA travels to cell’s
nucleus to activate its
genes; To reduce
immune response you
can remove the
proteins on the surface
that trigger it
Enters into cells easily;
affect wide range of diving
& not dividing cells; Once it
affects a cell, DNA travels
to nucleus where its genes
are activated; will integrate
virus DNA into host
genome (95% of the time in
the same location on
chromo 19, reducing the
disruption of other genes)
Disadvantages of Use
Might disrupt cell’s
genome if DNA is
inserted into random
spot; Might affect cell
division – causing
tumor growth; May
cause an immune
response – solution =
Reduce possibility of
response by removing
proteins on surface of
virus that trigger it
Immune responses can
prevent sustained
usage; Effective
temporary; DNA will
not integrate into host
cells genome (after a
week or two the cell
will discard it & gene
activation lost)
Need a “Helper” virus to
replicate themselves inside
cells; Will not cause an
immune response
© 2010 Project Lead The Way, Inc.
Medical Interventions Activity 2.2.1 Student Response Sheet – Page 1
Response Sheet modified from Genetic Science Learning Center – Gene Therapy: Molecular Bandage?
Vectors Used In Gene Therapy
How the vector carries
genetic material
Herpes Simplex Virus
dsDNA (oral & genital
herpes)
VIRAL
Liposome
Circular pieces of
dsDNA (plasmids) can
be packaged into
liposomes (mini lipid
packets similar to cell
membrane- will fuse to
cell membranes when
added to cells)
NON VIRAL
No max length
Naked DNA
Lone, circular dsDNA
(plasmid); not
packaged
NON VIRAL
Maximum length of
DNA that can be
inserted with this
vector
20,000 bp
No max length
Advantages of Use
Target & infect cells of
nervous system; Once
it infects a cell, DNA
travels to the nucleus
and activates genes;
DNA will stay in cell’s
nucleus for a long time
as a separate circular
piece of DNA that
replicates with cell
division; Will not
disrupt function of
other genes in cell;
Nonspecific for any cell
type; Once inside a cell,
plasmid DNA is
transported to nucleus
where genes are
activated; Best suited
for ex vivo gene
therapy approaches
Nonspecific to cells; ;
Once inside a cell,
plasmid DNA is
transported to
nucleus where genes
are activated; Best
suited for ex vivo
gene therapy
approaches
Disadvantages of Use
DNA will not integrate
into genome; Will
cause an immune
response (can remove
proteins from surface
to eliminate response)
Enter cells less
effective than virus;
Unless engineered to
do so, plasmid DNA will
not integrate into cell’s
genome (even if
engineered,
effectiveness is low);
Will not generate an
immune response;
Some are toxic
Enters cells less
effectively than virus;
Unless engineered to
do so, plasmid DNA
will not integrate into
cell’s genome (even
if engineered,
effectiveness is low);
Will not generate an
immune response;
© 2010 Project Lead The Way, Inc.
Medical Interventions Activity 2.2.1 Student Response Sheet – Page 2