You should consider using TBE (Tris-borate-EDTA) for RNA instead of TAE. Be sure about concentration (1x) and that it is prepared properly, it looks like a buffer issue.

Denaturing gel or not?

RNA has a lot of secondary structure, so if you're running on a regular gel, you usually want to denature it first.

Mix your RNA with 6x loading buffer plus as much formamide as you can cram in (instead of water). Aim for 60-75% formamide, final.

Heat to 65 degrees for 5mins, crash cool on ice.

Run as normal.

Hi, I want only to add a suggestion. If your coworkers do not pay attention to the equipment in the past, it wolud be better to wash your apparatus, gel tray and comb with NaOH and distilled water and tell everyone that these are used only for RNA, not for DNA. After this try to run again only one or two of the samples in the IMG (if you have enough RNA). I will try only to load RNA with glycerol and water without loading or marker and see if it is ok

If you can buy a RNA marker and a stock of dye not used by anyone

Valeria

Make sure all the material you are using is RNase free, from the look of the gel, you may be having RNase problem, especially RNase A. The running buffer and everything else must be RNase Free. You can filter your water, running buffer and any other liquid through 0.2 micron filter and make sure that tank for running the gel is also RNase free.

In response to Dr. David Farringdon Spencer, I completely agree with the clarification. I suppose that in this lab they didn't have appropriate solution that can help solve the problem, if this is the case, maybe the problem is something else.

Working in some laboratory very bad equipped, without any idea of how to handle RNA, I am drawn towards this "companion in misfortune"

Valeria