Hi, maybe this will help you: https://www.researchgate.net/post/What_could_cause_RNA_bands_to_not_migrate_on_a_denaturing_agarose_gel

Cheers, Nadine

Enjoy diving :-)

Thanks, the only answer that could fit is the suggestion of protein/RNA complexes that don't migrate. Although the nanodrop values weren't that bad to suggest this. It's certainly not a dye artefact since I post-stain my gels.

Hi Roger,

I think your “high” molecular weight bands could have different reasons that need different strategies to solve them:

If the bands are pure aggregates try to dissolve your RNA in RNase free buffer (10-20 mM, pH 7-8) and may heat the samples to 65°C if necessary.

If a protein contamination causes aggregation try to include a proteinase K treatment in your preparation.

Sometimes loading loading buffers containing urea or formaldehyde or formamide got too old and cause modification of RNA as well as electrophoreses artifacts. Prepare a new loading buffer with fresh de-ionised reagents.

Best,

Bodo