Taggart AJ, DeSimone AM, Shih JS, Filloux ME, Fairbrother WG.

Nat Struct Mol Biol. 2012 Jun 17;19(7):719-21. doi: 10.1038/nsmb.2327

Large-scale mapping of branchpoints in human pre-mRNA transcripts in vivo.

hnRNPs avoid the branching point. Reverse-transcriptase often mutates A to T when crossing the branchpoint (see supplementary material).