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RNA isolation - i want to show a gel (Jul/08/2005 )

Hi fellows,
I am performing RNA isolation with trizol reagent. I always run an aliquot of RNA in a native agarose gel to watch its integrity. I get bands corresponding to human ribosomal RNAs (28S, 18S and 5S) but I get an extra band that migrates faster than 5S-tRNAs. (please see it in the attached photo) I dont think that its a degradation product because the ratio of 28S/18S is higher than two. Besides there isnt a smear below any band. So I wonder if someone has found something like that and what could it be. thanks.

Attached Image


Hi assuming the far right is some kind of -ve control or a failed isolation could the banding youre refering to simply be the dye front?


I have to confess, I find your gel most curious and that band more curious still.

How many micrograms of RNA did you load and what is in those last 3 lanes? Also, how did you stain your gel. That does not look like EtBr.

It could be degraded RNA, but with 28 and 18S band looking so tight, I doubt it.

Also, if it was loading dye, I would expect it in the last three lanes.


Hi again
The gel is stained with EtBr. I ve inverted the colours to safe ink. I runned 8 ug per lane and rigthest are failed isolations ('re paralel isolations but from HL60, which are difficult for this porpouse). as you said the lower band it is not dye but it doesnt seem to be a degradation product. it is an enigma for the people in my lab even for the more experienced.


Re run the gel. Load 1ug and see what happens.

8ug of RNA is alot to load on a gel. I am hoping this is an artifact due to the high mass.