does glycogen in RNA sample interfere with Northerns?

Rob Steele resteele at
Mon Apr 18 16:04:17 EST 1994

We have been using the Pharmacia QuickPrep Micro mRNA purification kit
for isolation of polyA+ RNA for Northern analysis.  When we use small
amounts of starting material we add the glycogen that comes with the
kit as a carrier.  RNA from such preparations gives no signal on a
Northern, even when probed for abundant RNAs.  We know that the gel
runs ok and the transfer is taking place since marker RNAs show up fine
when the blot is stained with methylene blue.  Among various
possibilities, I was wondering if the formaldehyde in the sample buffer
and the gel buffer might be cross-linking the glycogen to the RNA and
causing it to be retained in the well of the gel as a large complex. 
Does anyone know if glycogen in an RNA sample can cause such a problem?

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