What can be considered RNase-free? - (Feb/09/2006 )

Ok, I'm full of RNA questions this week..

I was taught in graduate school that tubes, gloves, and paper towels from freshly opened packages can generally be considered RNase-free. Is that true?

Also, what about bench pads (we call them "blue pads", but I'm not sure if that is their real name or not) that are made with cotton in them? Even if these are from new packages, cotton is a natural product right? What do you think of possible RNase-contamination there?

Thanks!!

hi soulene,

call me paranoid...but i consider everything to be contaminated with RNase unless treated.. The only thing i dont consider contaminated is something that says rnase free eg microfuge tubes and i am opening it for the first time inside a hood. We call those blue bench things diapers....nope i dont trust those....i normally work on a naked bench after i clean it with rnazap...

hi
i pay particular attention to tips. For my RNAse free boxes, i open a new bag of them and place them myself clean under a hood.
I autoclave all.
For water... well i don't trust very much the DEPC long term treatment. That's why i treat a serie of tiny 100ml bottles and use one as RNAse free per exp. After one opening, the bottle goes in "clean water" way
i consider that all opened stuff may be contaminated.
For bench : i clean it with detergent and dry it with ethanol. After that, i place a piece of aluminium paper and this it he delimited RNase free area.
goes well for me.

Finally, i tell my bench-neighbours that it's a tough exp and that only a single drop of water from ext would drive me crazy.
goes well for me too (and for them too ).

Agree with Pria, everything that doesn't specifically state RNase free has a chance for being contaminated with it...

Thanks for your replies!

Ok, so I'm getting picky because I'm setting up our RT-PCR methodology to be GLP compliant, and I am interested in your/anyone's opinion on this:

The RNase-Zap protocol says to wipe areas clean after RNase treatment with clean paper towels. So, they must assume that clean paper towels are RNase-free?? I guess this is a question for Ambion! But I'm very interested in what others here think..