Minimum Amount of RNA to be Visible on Agarose Gel?

[liono]

Hello all,

does anyone know what is the lowest concentration of RNA which is needed for RNA to be visible on an agarose gel?

[ampasaladr]

I have used 1ug total RNA to run and seen on gel with EtBr stain

[Jon Moulton]

Both molar concentration and length of RNA fragment will influence visibility. If you load the gel with a known mass of RNA instead of by a volume of some molar concentration, you can determine the mass needed for visibility and use that for subsequent experiments. However, a particular volume and concentration of a short sequence of RNA will have less bases for a base-associated dye (e.g. EthidiumBr) to bind with than the same volume and concentration of a long sequence of RNA; therefore keeping volume constant, compared to the longer sequence you will need a higher concentration of the short sequence in order to see the band.