2. INTRODUCTION
Genetic engineering and
biotechnology will continue to
contribute in the future to medicine,
industry, and agriculture, as well
as to basic research. In this section
some practical applications are
briefly discussed.
3. MEDICAL FIELD
The production of medically useful proteins such as somatostatin,
insulin, human growth hormone, and some interferons (signaling
molecules of the immune system) is of great practical importance
(table 14.4). This is particularly true of substances that previously
only could be obtained from human tissues. For example, in the
past, human growth hormone for treatment of pituitary dwarfism
was extracted from pituitaries obtained during autopsies and was
available only in limited amounts. Interleukin-2 (a protein that
helps regulate the immune response)
4. AGRICULTURAL FIELD
Cloned genes can be inserted into plant as well as animal cells. A
popular way to insert genes into plants is with a recombinant Ti
plasmid (tumor-inducing plasmid) obtained from the bacterium
Agrobacterium tumefaciens (Techniques & Applications 14.2).
It also is possible to donate genes by forming plant cell protoplasts, making them
permeable to DNA, and then adding the desired recombinant DNA. The gene gun is also
used in the
production of transgenic plants.
5. MEDICAL FIELD
AGRICULTURAL FIELD
• Synathesis of somatostatin gene
• Somatostatin gene by recombinant ecoli
• Bioengineering plants
• Proteins and peptides
• Social impact on dna technology
6. CLONING OF SOMATOSTATIC GENE
7 Cloning the Somatostatin Gene. An
overview of the procedure used to synthesize a
recombinantplasmid containing the somatostatin gene. Apr
, Tetr
, ampicillin- and
tetracycline-resistance genes, respectively.
7. SYNTHESIS OF GENE BY RECOMBINANT ECOLI
The Synthesis of Somatostatin by Recombinant E.
coli. Cyanogen bromide cleavage at the methionine
residue
releases active hormone from the -galactosidase
fragment. The gene and associated sequences are
shaded in color. Stop codons, the
special methionine codon, and restriction enzyme
sites are enclosed in boxes.
9. BIOENGINEERED PLANT
(a) The large plasmid (Ti) of
this bacterium can be
used as a cloning vector
for foreign genes that
code for herbicide or
disease resistance.
(b) The
recombinant
plasmids
are taken up by
the
Agrobacterium
cells,
which multiply
and copy
the foreign
gene.
(c) Genetically
engineered
Agrobacterium
is
inoculated into
a culture
of target plant
cells and
infects the cells.
d) Fusion of the bacterium
with the plant cell wall
permits entrance of the Ti
plasmid and incorporation
of the herbicide gene into
the plant chromosome.
Mature plants can be
grown from single cells,
and these transgenic
plants will express the
new gene.
(e) Because the
gene will be
part
of the plant’s
genome, it
will be
transmitted to
offspring in
seeds.
10.
11. SOCIAL IMPACT ON DNA TECHNOLOGY
• .10 SOCIAL IMPACT OF RECOMBINANT
• DNA TECHNOLOGY
• Despite the positive social impact of recombinant DNA technology, the potential to alter an organism genetically raises serious
• scientific and philosophical questions. These issues are the subjects of vigorous debate, as briefly reviewed here.
• In contrast to the use of biotechnology in basic and applied science, the use of gene therapy in human beings raises pressing ethical and moral questions. These problems are not extreme as long
• as adult stem cells are used. However, as witnessed in American
• political discourse and legislation since 2001, the use of embryonic stem cells is problematic. Is it morally acceptable to sacrifice
• an embryo to obtain these cells? Proponents point out that adult
• stem cells are rare and are not truly pluripotent. They also note that
• these donated embryos are unwanted and will eventually be destroyed by the fertility clinics where they are frozen. Those opposed to embryonic stem cell research believe just as strongly that
• human life should not be destroyed, even at the very earliest
• stages. In the summer of 2001, President G. W. Bush banned
