A bipartite U1 site represses U1A expression by synergizing with PIE to inhibit nuclear polyadenylation.

@article{Guan2007ABU,
  title={A bipartite U1 site represses U1A expression by synergizing with PIE to inhibit nuclear polyadenylation.},
  author={Fei Guan and Rose M Caratozzolo and Rafal M. Goraczniak and Eric S. Ho and Samuel I. Gunderson},
  journal={RNA},
  year={2007},
  volume={13 12},
  pages={2129-40}
}
U1A protein negatively autoregulates itself by polyadenylation inhibition of its own pre-mRNA by binding as two molecules to a 3'UTR-located Polyadenylation Inhibitory Element (PIE). The (U1A)2-PIE complex specifically blocks U1A mRNA biosynthesis by inhibiting polyA tail addition, leading to lower mRNA levels. U1 snRNP bound to a 5'ss-like sequence, which we call a U1 site, in the 3'UTRs of certain papillomaviruses leads to inhibition of viral late gene expression via a similar mechanism… CONTINUE READING