Transcript 6.2 Genetic Engineering

6.2 Genetic Engineering
Genetic Engineering
Altering the sequence of
DNA molecules
Important in developing
drugs

Insulin
 Human insulin produced by
bacteria

Somatropin
Genetic Engineering Pioneers
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Experiments for selecting,
recombining and transforming
new genes into bacteria
Techniques are still used in
molecular biology labs
One of the most important discoveries in
biomedical research
1978 – “Genentech” biotechnology company
produced somatostatin
http://www.dls.ym.edu.tw/lesson/bacgen.files/10-20.gif
1970s – Stanley Cohen (plasmids) and
Herbert Boyer (restriction enzymes)
Somatropin
A drug that is identical to
human growth hormone
(somatotropin)
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Treats growth deficiency from
dwarfism and Turner’s syndrome
First human hormone produced
by genetic engineering  safe
and abundant production
Somatropin
production
Excise human growth
hormone gene using
restriction
endonucleases
Signal sequence is
removed
Insert gene after the
lac promoter in a
plasmid transformed
into E. coli cells
E. coli are grown in
media containing IPTG
(isopropyl
thiogalactoside)
Somatropin production (cont’d)
IPTG is an inducer of the lac promoter but is
not consumed by E.coli
Control production of hormone
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Presence of IPTG somatropin production
Absence of IPTGno somatropin production
Somatropin is then isolated from bacteria and
sold to patients
somatropin
RNA
polymerase
lacZ
lacY
lacA
lacI protein
IPTG
mRNA
Somatropin, ß-galactosidase,
permease, transacetylase are
synthesized