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

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 lacZ lacY lacA somatropin RNA polymerase lacI protein IPTG mRNA Somatropin, ß -galactosidase, permease, transacetylase are synthesized