Downstream sequence elements with different affinities for the hnRNP H/H′ protein influence the processing efficiency of mammalian polyadenylation signals

• Published in: Nucleic acids research 2002-04, Vol.30 (8), p.1842-1850
• Main Authors: Arhin, George K., Boots, Monika, Bagga, Paramjeet S., Milcarek, Christine, Wilusz, Jeffrey
• Format: Article
• Language: English
• Subjects: 3' Flanking Region; Animals; Base Sequence; Binding Sites; Cell Line; Conserved Sequence; Guanosine Triphosphate - metabolism; Heterogeneous-Nuclear Ribonucleoprotein Group F-H; Heterogeneous-Nuclear Ribonucleoproteins; hnRNP H/H' protein; Mice; Molecular Sequence Data; Polyadenylation; Regulatory Sequences, Nucleic Acid; Ribonucleoproteins - genetics; Ribonucleoproteins - metabolism; Transcriptional Activation; Uridine Triphosphate - chemistry
• ISSN: 0305-1048; 1362-4962; 1362-4962
• DOI: 10.1093/nar/30.8.1842

Auxiliary factors likely play an important role in determining the polyadenylation efficiency of mammalian pre-mRNAs. We previously identified an auxiliary factor, hnRNP H/H′, which stimulates 3′-end processing through an interaction with sequences downstream of the core elements of the SV40 late polyadenylation signal. Using in vitro reconstitution assays we have demonstrated that hnRNP H/H′ can stimulate processing of two additional model polyadenylation signals by binding at similar relative downstream locations but with significantly different affinities. A short tract of G residues was determined to be a common property of all three hnRNP H/H′ binding sites. A survey of mammalian polyadenylation signals identified potential G-rich hnRNP H/H′ binding sites at similar downstream locations in ∼34% of these signals. All of the novel G-rich elements tested were found to bind hnRNP H/H′ protein and the processing of selected signals identified in the survey was stimulated by the protein both in vivo and in vitro. Downstream G-rich tracts, therefore, are a common auxiliary element in mammalian polyadenylation signals. Sequences capable of binding hnRNP H protein with varying affinities may play a role in determining the processing efficiency of a significant number of mammalian polyadenylation signals.