Lab 5: Series 3-Investigating Gene Regulation Using RNAi
In the age of genome sequencing we now know, or can make educated guesses about, the location of every gene in an organism's genome; however, this does not give us any information about the function of the gene product (protein) in the organism. We can use reverse genetic analysis to help us solve this puzzle. There are several tools in the reverse genetics toolbox: directed mutation (point mutations or deletions), overexpression using transgenes, and gene silencing using knockout organisms or double stranded RNA (RNAi). Only RNAi and overexpression have been perfected in C. elegans. Scientists still have not found a way to do in vivo homologous recombination in worms.
We are going to use RNAi as our tool to investigate gene function and how genes are regulated via reverse genetics. C. elegans is the first animal in which the process of RNAi was discovered. A similar system was identified in plants years earlier but, sadly, was largely ignored by the scientific community. We now know that RNA regulation in cells is a fundamental method of regulating gene expression in organisms from microscopic C. elegans to humans. Many labs are now working non-stop to develop treatments for many "incurable" diseases using RNAi.
Calibration of Micropipettes
- To calibrate your P1000, P 200, and P 20 micropipets, label 6 microfuge tubes (1-6) and weigh them. Record the weights in the table below.
- Following the table below, pipet the specified volumes into the pre-weighed microfuge tubes prepared above and then re-weigh them. Record all weights.
- Calculate the weight of the water in grams. 1000 microliters of water should weigh 1 gram at room temperature.
- If the water in any tube weighs more or less than 1 gram, ask your instructor for help. If your calibration is significantly off after several repeated attempts, your pipet (or your technique!) may need adjustment.
| Tube # || Tube Pre-Weight || Vol. in μL using P20 || Vol. in μL using P200 || Vol. in μL using P1000 || Weight of Tube + Water in grams || Weight of Water in grams
|| || 10 || 0 || 990 || ||
|| || 0 || 100 || 900 || ||
|| || 20 || 175 || 805 || ||
|| || 2 || 88 || 910 || ||
|| || 0 || 200 (5 times) || 0 || ||
|| || 20 (5 times) || 0 || 900 || ||
For a Word™ format protocol: Media:Protocol for Micropipet Calibration.doc