1. Production of Human Growth Hormone in Genetically Modified Bacteria

2. mRNA coding for hGR is extracted from human pituitary gland cells
DNA copies of the mRNA are made using the enzyme reverse transcriptase
cDNA

3. cDNA is cut with a restriction endonuclease.
(‘restriction enzyme)
This produces
sticky ends
Sticky ends
(single-stranded ends which will pair up with complementary sequences)

4. small loop of DNA found in bacterial cells
Plasmid:
small loop of DNA found in bacterial cells
- the origin of replication
Origin of Replication
Plasmids contain sequences of bases which signal to the cell that this DNA needs to be copied when the cell divides

5. Cut plasmid with restriction enzyme to produce fragments with sticky ends
Mix with cDNA copies of hGR genes…
…complementary sticky ends will pair up by hydrogen bonding

6. Add enzyme, DNA ligase
DNA ligase joins two fragments of DNA by making a covalent bond between ends of their phosphate-pentose backbone
Recombinant DNA is formed

7. Mix recombinant plasmids with suitable bacteria e.g. E. coli
Induce bacteria to take up plasmids
 Heat shock
 Electrical shock
 Chemical treatment

8. Recombinant plasmid is copied as cells divide
Bacteria are cultured
Recombinant plasmid is copied as cells divide
hGR produced by genetically modified bacteria
Modified bacteria produce hGR