Lecture--Chapter 19 Flashcards
use molecular techniques to produce new combinations of DNA fragments
recombinant DNA technology
What are the aspects of recombinant DNA technology?
- Disease diagnostics and gene therapy
- Make recombinant vaccines
- Express proteins in cells for therapeutic products (human insulin)
- Make transgenic organisms with value added traits
- Clone ORFs and regulatory regions for study
methods used to assemble recombinant DNA molecules and direct their replication within host organisms
gene cloning
Gene cloning involves both ____ DNA and ____ DNA.
chromosomal; vector
a DNA molecule used to transfer foreign DNA into another cell, where it can be replicated and/or expressed
vector DNA
small, circular, double-stranded DNA molecules in bacteria that carry genes which benefit survival of the bacterium
plasmids
What are the important features of plasmids?
- Strong origins of replication
- Multiple cloning sites
- A selectable marker
Important features of plasmids: Strong origins of replication:
enable their expression in high copy numbers
Important features of plasmids: Multiple cloning sites:
enable using different restriction enzymes to digest the DNA
Important features of plasmids: A selectable marker:
is a gene that codes for a product (e.g. antibiotic) that allows only transformed bacteria to survive
enzymes that cut DNA at or near specific recognition nucleotide sequences known as restriction sites
restriction enzymes (restriction endonuclease)
What are the aspects of Type II RE’s?
- recognition sites that are usually undivided, palindromic, 4-8 nt long
- recognise and cleave DNA at the same site, require Mg2+ as a cofactor
What are the steps of production of rDNA?
- Incubate both DNAs and EcoRI, which cuts the DNA backbone between G and A.
- Incubate the DNAs together, allowing sticky ends to hydrogen bond.
- Add DNA ligase, which covalently links the DNA backbones.
Steps for gene cloning: Prepare Insert DNA:
PCR amply and do restriction digest of DNA fragment to be cloned
What are the steps for gene cloning?
- Prepare Insert DNA
- Prepare Plasmid DNA
- Clean up
- Transform
- Plate
- Pick colonies, check by PCR
- Grow, isolate
Steps for gene cloning: Prepare Plasmid DNA:
purify in quantity, do restriction digest
Steps for gene cloning: clean up:
both insert and plasmid DNA (gel/column purify), mix plasmid and insert in varying ratios, ligate
Steps for gene cloning: transform:
competent cells of E. coli
Steps for gene cloning: plate:
onto media with selectable marker (e.g. ampicilin)
Steps for gene cloning: pick colonies, check by PCR:
for presence of insert DNA
Steps for gene cloning: grow:
in large culture, isolate cloned plasmid