(83)
14. Forklare betigneslerne for at klonede DNA-sekvenser vil kunne
udtrykkes i bakterier og eukaryote celler (kloning og ekspression af human
insulin; kloning og ekspression af human væksthormon)
Stryer, s. 158, fig. 6.23
Devlin, s. 309-311, fig. 7.22
Stryer, s.157; s.160-fig.6.28
Growth hormone
-
a 21 kDa protein is normally synthesized by the pituitary gland. A deficiency of
the protein causes dwarfism, excess of it gigantism. The gene for rat growth
hormone can be placed in a plasmid and introduced into the male pronucleus of
the zygote.
The gene is inserted into a plasmid next to a mouse metallothionein promoter which can be activated by addition of heavy metals, fx. cadmium jon into the drinking water.
Proinsulin,
a precursor of insulin, is synthesized by bacteria harbouring plasmids that
contain DNA complementary to the mRNA for proinsulin found in human pancreas.
Indeed bacteria produce much of the insulin used today by millions of diabetics.
tilbage til molekylær biologi