I am trying to label RNA with 4SU (by IVT) and then doing Poly A tailing. However, i can see 4SU labelling of my RNA in IVT step but when I do Poly A tailing. I find it difficult to isolate the RNA as there is no visible pellet (procedure is light sensitive) and at the end the conc is either nil or very low. I am using trizol method to isolate PolyA tailed 4Su labelled RNA as earlier I do the choloform -isopropanol method where unincorporated dNTPS giving the high nanodrop reading whereas in gel there is no band.