A physical and functional link between splicing factors promotes pre-mRNA 3' end processing.
Polypyrimidine tract-binding protein (PTB) is a splicing regulator that also plays a positive role in pre-mRNA 3' end processing when bound upstream of the polyadenylation signal (pA signal). Here, we address the mechanism of PTB stimulatory function in mRNA 3' end formation. We identify PTB as the protein factor whose binding to the human beta-globin (HBB) 3' UTR is abrogated by a 3' end processing-inactivating mutation. We show that PTB promotes both in vitro 3' end cleavage and polyadenylation and recruits directly the splicing factor hnRNP H to G-rich sequences associated with several pA signals. Increased binding of hnRNP H results in stimulation of polyadenylation through a direct interaction with poly(A) polymerase. Therefore, our results provide evidence of a concerted regulation of pA signal recognition by splicing factors bound to auxiliary polyadenylation sequence elements.
Millevoi
Stefania
S
INSERM, U563, Toulouse, Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan, Toulouse, F-31300, France. stefania.millevoi@inserm.fr
Decorsière
Adrien
A
Loulergue
Clarisse
C
Iacovoni
Jason
J
Bernat
Sandra
S
Antoniou
Michael
M
Vagner
Stéphan
S
D020413:3' Untranslated Regions / Q000737:chemistry; D001483:Base Sequence; D017124:Conserved Sequence; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H / Q000378:metabolism; D006801:Humans; D011061:Poly A / Q000378:metabolism; D026723:Polyadenylation; D038941:Polypyrimidine Tract-Binding Protein / Q000378:metabolism*; D026721:RNA 3' End Processing; D012322:RNA Precursors / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D038621:Regulatory Sequences, Ribonucleic Acid; D055544:beta-Globins / Q000235:genetics*
D020413:3' Untranslated Regions; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D012322:RNA Precursors; D012333:RNA, Messenger; D038621:Regulatory Sequences, Ribonucleic Acid; D055544:beta-Globins; D038941:Polypyrimidine Tract-Binding Protein; D011061:Poly A