Probe labeling - (Jun/14/2001 )
If the control does not work it means your entire protocol is defective. Buy a fresh kit and try it again. If you want it really simplywe have found that the Sigma "all-in-one" kits work really well and theyare almost impossible to mess up.
I have been trying to label a probe (190bp) with radioactive cytidine for use in a Northern blot. However, the probe was slightly labeled so I tried the control DNA (3Kb) and that was not labeled as much as it should be (the geiger showed about 100 counts a minute for 25ng of labeled sample). Any ideas why I cant get hot probe?
try end labeling of your probe. it works better for short fragments. Or lower the amount of random primers if you are using random primed labeling.