Medical Biotechnology Flashcards
Gene Therapy
1)Introduction of genes into existing cells to prevent or cure a wide range of diseases
2)It is a technique for correcting defective genes responsible for disease development
What are the two types of gene therapy?
Depending on which types of cells are being treated:
1)Somatic gene therapy
2)Germline gene therapy
Somatic gene therapy
1)Transfer of a section of DNA to any cell of the body that doesn’t produce sperm or egg
2)Effects of gene therapy will not be passed onto the patient’s children
Germline gene therapy
1)Transfer of a section of DNA to cells that produce eggs or sperm
2)Effects of gene therapy will be passed onto patient’s children and subsequent generations
Concept of DNA, RNA and protein
1)Messenger RNA (mRNA) plays a vital role in translating the instructions in DNA into the proteins of life
2)If a gene is damaged it creates damaged mRNA, which goes on to create damaged proteins, and ultimately disease
3)Gene therapy will carefully select to correct the effect of a mutated gene that is causing disease
Tools for gene editing
Vector-vehicles used in gene therapy to transfer the desired gene into a target cell
2 main classes of vectors
1)Viral vectors
2)Non-viral vectors
Viral vectors
1)Retrovirus vector system
2)Adeno virus vector system
3)Adeno associated virus vector
4)Herpes simplex virus vector
Non-viral vectors
1)Pure DNA construct
2)Lipid noemulsions
3)DNA polymer conjugates
4)Human artificial chromosome
Viral vs. Nonviral vector system (Definition)
1)Viral vectors are gene-delivery vehicles that deliver foreign genetic material into cells using a viral genome
2)Nonviral vectors are gene-delivery vehicles that deliver foreign genetic material into a cell by using inorganic, particles, lipid-based vectors, polymer-based vectors, and peptide-based vectors
Viral vs. Nonviral vector system (Chemical, Biological, Physical Agent)
Viral vectors: Biological agent
Nonviral Vectors: Chemical agent
Viral vs. Nonviral vector system (Biosafety)
Viral Vectors: Has risk to Biosafety
Nonviral Vectors: Has no risk to Biosafety
Viral vs. Nonviral vector system (Efficiency and Specificity)
Viral Vectors: More efficient and highly specific
Nonviral Vectors: Less efficient and barely specific
Single Dose/ Multiple Dose
Viral Vector: Single dose delivery sufficient
Nonviral vector: Multiple or repeated doses are required in delivery
Medical Biotechnology-gene editing tools
1)DNA editing uses nucleases (molecular scissors)
2)Zinc finger nucleases (ZFNs)
3)Transcription activator-like effector nucleases (TALENs)
4)Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)
DNA editing using nucleases (molecular scissors)
Enzymes capable of cleaving the phosphodiester bond between nucleotides of nucleic acids
1)Exonucleases: digest nucleic acids from the neds
2)Endonucleases: act on regions in the middle of target molecules
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)
1)CRISPR is a hallmark of bacterial defense system that forms the basis for CRISPR-Cas9 genome editing technology
2)CRISPR was first discovered in archaea, a bacterial immune system known to defend against invading viruses
3)CRISPR-Cas9 is a system that can be programmed to target specific stretches of genetic code and to edit DNA at precise locations
How does CRISPR/Cas9 system work?
1)Target the right gene
2)Bind the target
3)Cut the DNA
4)Repair and edit the DNA
1)Target the right gene
Scientists engineer a piece of RNA that is a match for the DNA they want to edit. This is called the guide RNA.
2)Bind the target
An enzyme called Cas9 binds to a piece of DNA and temporarily unwinds a section of the DNA.
3)Cut the DNA
If the guide RNA matches a section of the DNA, the Cas9 enzyme cuts both strands of the DNA double helix.
4)Repair and edit the DNA
Machinery inside the cell rushes to fix the broken DNA. One repair process uses a similar-looking, unbroken piece of DNA as a template to stitch the broken pieces back together.
Scientists can introduce tailor-made DNA into the cell — tricking the repair machinery into using the engineered DNA as the template for stitching together the broken pieces.
