170 likes | 262 Views
Common Techniques Used in Cell Physiology. First… a reminder. Nucleic Acids have polarity-comes from where next base can be added- “start” on the 5’ end- you can only add bases to the 3’ end 4-3 p. 102. Double stranded DNA (or RNA:DNA duplexes) are arranged antiparallel 5’ CAGT 3’
E N D
Common Techniques Used in Cell Physiology First… a reminder Nucleic Acids have polarity-comes from where next base can be added- “start” on the 5’ end- you can only add bases to the 3’ end 4-3 p. 102
Double stranded DNA (or RNA:DNA duplexes) are arranged antiparallel 5’ CAGT 3’ 3’ GTCA 5’ Often, only one strand is listed (Genbank)- this is conventionally the top strand (sense strand) and it reads 5’ 3’ left to right.
With this you can understand PCR-one of the most powerful and common techniques used in cell phys research today. Dr. Tom Brock- microbiologist looking for extremophiles- found Thermus aquaticus in Yellowstone hot springs-thriving at 70 C! Chien and Trella- Univ. Cincinnati first isolated DNA polymerase from Taq Kary Mullis- Cetus corporation-first figured out how to use Taq in PCR reaction Hoffman LaRoche- bought rights to PCR for 300 million
You can also use the same sort of idea to convert mRNA into DNA (cDNA) (7-15 p. 221)
Now you take each one of those pieces and clone it (view plasmid cloning animation)
Often each of these cloned cDNA is packaged into a virus-you then have a cDNA library 7-16,222
What’s a cDNA library good for? Say you are looking for a protein that shows up in liver during cancer. Make a cDNA library and screen it for this protein. 7-18, 225
If you are screening for DNA must have a probe (piece of complementary DNA that you think will stick to the right thing) You can also look for proteins in libraries 7-21, 228
Many of these techniques require that you know how the sequence of DNA at some stage of the game. You determine that (usually) with Sanger (dideoxy) sequencing 7-29,234
DNA microarrays (aka DNA chips) Fig. 7-39 p. 249 A relatively new method to screen thousands of genes simultaneously
Group Exercise #2 Look at the article I handed out (Lipshutz et. al, 1999. Nature Genetics. 21: 20-24 This is a complex article, but we can pull it apart In groups of 4: Group 1- How do you make a microarray? Group 2-How do you screen an array? Group 3-What are the applications for arrays?