6.2 Genetic Engineering

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14 Δεκ 2012 (πριν από 4 χρόνια και 10 μήνες)

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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


1970s


Stanley Cohen (plasmids) and
Herbert Boyer (restriction enzymes)


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
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Somatropin

A drug that is identical to
human growth hormone
(somatotropin)


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


Presence of IPTG


somatropin production


Absence of IPTG

no

somatropin production

Somatropin is then isolated from bacteria and
sold to patients

lac
Z


lac
Y



lac
A

somatropin

RNA
polymerase

lac
I protein

IPTG

mRNA

Somatropin,
ß
-
galactosidase,
permease, transacetylase are
synthesized