A novel principle for conferring selectivity to poly(A)-binding proteins: interdependence of two ATP synthase beta-subunit mRNA-binding proteins.
Based on electrophoretic mobility-shift assays and UV cross-linking experiments, we present evidence in the present work for the existence of two mammalian cytosolic proteins that selectively interact with the 3'-untranslated region of the mRNA coding for the catalytic beta-subunit of mitochondrial ATP synthase (beta-mtATPase). One of the proteins, beta-mtATPase mRNA-binding protein (BARB)1, is a novel poly(A)-binding protein that specifically binds the poly(A) tail of the beta-mtATPase transcript. BARB1 achieves this mRNA selectivity through its interaction with a second protein, BARB2, that binds the beta-mtATPase mRNA through a 22-bp element with a uridylate core, located 75 bp upstream of the poly(A) tail. Conversely, in the absence of BARB1, BARB2 is still able to bind the beta-mtATPase mRNA, but does so with lower affinity. Thus the interaction between BARB1 and BARB2 and beta-mtATPase mRNA involves the formation of a complex between the two BARB proteins. We conclude that BARB1 and BARB2 selectively bind the 3'-untranslated region of beta-mtATPase mRNA in a novel and interdependent manner. The complex between these two proteins may be involved in post-transcriptional regulation of gene expression.
Andersson
U
U
The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, S-106 91 Stockholm, Sweden.
Antonicka
H
H
Houstek
J
J
Cannon
B
B
D020413:3' Untranslated Regions / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003600:Cytosol / Q000737:chemistry; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity; D011061:Poly A / Q000235:genetics / Q000378:metabolism*; D039102:Poly(A)-Binding Proteins; D006180:Proton-Translocating ATPases / Q000235:genetics*; D015347:RNA Probes / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D013379:Substrate Specificity; D014466:Ultraviolet Rays; D014542:Uridine Monophosphate / Q000235:genetics / Q000378:metabolism
D020413:3' Untranslated Regions; D039102:Poly(A)-Binding Proteins; D015347:RNA Probes; D016601:RNA-Binding Proteins; D011061:Poly A; D014542:Uridine Monophosphate; D006180:Proton-Translocating ATPases