title: Downstream sequence elements with different affinities for the hnRNP H/H' protein influence the processing efficiency of mammalian polyadenylation signals.
abstract: 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 approximately 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.
authors.affiliation: Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA.
authors.forename: George K
authors.initials: GK
authors.lastname: Arhin
authors.forename: Monika
authors.initials: M
authors.lastname: Boots
authors.forename: Paramjeet S
authors.initials: PS
authors.lastname: Bagga
authors.forename: Christine
authors.initials: C
authors.lastname: Milcarek
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Wilusz
mesh_terms: D024509:3' Flanking Region; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D017124:Conserved Sequence; D006160:Guanosine Triphosphate / Q000378:metabolism; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D051379:Mice; D008969:Molecular Sequence Data; D026723:Polyadenylation; D012045:Regulatory Sequences, Nucleic Acid; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014544:Uridine Triphosphate / Q000737:chemistry
chemical_list: D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012261:Ribonucleoproteins; D006160:Guanosine Triphosphate; D014544:Uridine Triphosphate