[mewzilla]

This abstract might explain a lot from 2012...

[The effects of SV40 PolyA sequence and its AATAAA signal on upstream GFP gene expression and transcription termination]

...SV40 PolyA (Simian virus 40 PolyA, also called PolyA) sequence is DNA sequence (240 bp) that possesses the activity of transcription termination and can add PolyA tail to mRNA....

Contamination, my arse.

[mewzilla]

More here...

Plasmids 101: Terminators and PolyA signals

We may have an explanation for CoupFlu vaxx-rekated turbo cancers...

[Myrddin]

I ran across another molecular biology paper that explained the interest in a PolyA tail. You can get a reagent that has a ferromagnetic end tied to a poly-U or poly-T sequence. Mix that with the PolyA tails and they adhere. Pass the solution with the "adhered" attachments to your PolyA product over a magnet to capture the product. Introduce a different buffer solution and the PolyA product released from the magnetic poly(U/T). Significantly purified. Add a good DNAase to clear out the DNA from the RNA. Purification steps you can do on your lab bench. Apparently, not applied to successfully on an industrial scale.