Transcript gene therapy2

In most gene therapy studies, a "normal"
gene is inserted into the genome to replace an
"abnormal," disease-causing gene. A carrier
molecule called a vector must be used to deliver
the therapeutic gene to the patient's target cells.
Currently, the most common vector is a virus
that has been genetically altered to carry normal
human DNA
Retroviruses - Retroviruses are known to lead to certain types of
cancers in both humans and animals, as well as a range of viral
infections. Human Immunodeficiency Virus (HIV), the virus that
causes Acquired Immune Deficiency Syndrome (AIDS), is one
example of a retrovirus.
Adenoviruses - A class of viruses with double-stranded DNA
genomes that cause respiratory, intestinal, and eye infections in
humans. The virus that causes the common cold is an adenovirus.
Adeno-associated viruses - A class of small, single-stranded DNA
viruses that can insert their genetic material at a specific site on
chromosome 19.
Herpes simplex viruses - A class of double-stranded DNA viruses
that infect a particular cell type, neurons. Herpes simplex virus type 1
is a common human pathogen that causes cold sores.
Ethical considerations for using
Gene therapy.
People have had to deal with genetic inequality as a fact of life.
With the advent of gene therapy, this may no longer be the case for
some people. Most people feel that it is okay to use gene therapy
to treat human genetic diseases. Somewhat surprisingly. Some
individuals, however, are concerned that the technique may be
used for "treatment" of genetic "disorders" other than diseases.
Because many people are concerned about the safety of gene
therapy, a special committee of the National Academy of Science
was created to look into the consequences of releasing rDNA
engineered organisms into the environment. The committee
concluded that "there is no evidence that unique hazards exist
either in the use of rDNA technique or in the transfer of genes
between unrelated organisms," and that, "the risks associated with
the introduction of rDNA engineered organisms are the same kind
as those associated with the introduction of unmodified
organisms.
The use of gene therapy has five basic steps,
and there are a variety of methods to achieve
each step.
· Step 1:
The gene coding for the desired
protein is isolated.
· Step 2:
The gene is delivered to a target cell by
means of a vector.
This vector carries the gene and gets it
into the cell.
· Step 3:
The cell integrates this gene and begins to produce
DNA and RNA coding for the protein.
· Step 4:
The protein is made by the cell
.
· Step 5:
This protein acts inside the cell or is released
into the environment and
then stimulates the desired action such as
spinal fusion or disc
regeneration.