Gene therapy treatments for cystic fibrosis

• copying genes and inserting them into other organisms is known as genetic engineering or genetic modification and its the first stage of gene therapy
• Restriction enzymes endonucleases are used to chop up healthy DNA, cutting them at specific sites in small pieces which can be handled more easily
• each restrictive endonuclease will only cut the DNA at a specific (restricted) site within the DNA sequence
• some restriction enzymes cut the DNA so it leaves a couple of base pairs known as a sticky end which enables other DNA to be attached
• Artificial copies of healthy genes can also be made via taking mRNA molules transcribed from the gene and using the enzyme reverse transcriptase to make complementary base pairs



• next stage in gene therapy is to attatch another piece of DNA to the gene this is called a vector which will carry the gene to its target cell
• Plasmids the circular strand of DNA found in bacteria are often used as vectors- once the plasmid gets into the hst cell it can combine its DNA with the cell to form recombinant DNA 
• they are needed to carry new DNA into a human cell

• for CF harmless viruses and liposomes (spheres from lipid bilayer) are used , the virus infects the lung epithelials cells and inserts the viral DNA included the added gene
• liposomes fuse with the cell membrane and can pass through and diliver the new DNA into the cytoplasm 
• at the moment the virus is the most effective way of transporting the gene
• specific markers can be added with the new gene to make insertion of the gene easier
• Once the healthy DNA is inside the lung epithelials the healthy gene should be transcribed and translated producing a normal active CFTR protein releaving some of the symptoms