Production of Human Growth Hormone in Genetically Modified Bacteria

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

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)

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

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

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

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

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