Oligomerization of EDEN-BP is required for specific mRNA deadenylation and binding.
BACKGROUND
mRNA deadenylation [shortening of the poly(A) tail] is often triggered by specific sequence elements present within mRNA 3' untranslated regions and generally causes rapid degradation of the mRNA. In vertebrates, many of these deadenylation elements are called AREs (AU-rich elements). The EDEN (embryo deadenylation element) sequence is a Xenopus class III ARE. EDEN acts by binding a specific factor, EDEN-BP (EDEN-binding protein), which in turn stimulates deadenylation.


RESULTS
We show here that EDEN-BP is able to oligomerize. A 27-amino-acid region of EDEN-BP was identified as a key domain for oligomerization. A mutant of EDEN-BP lacking this region was unable to oligomerize, and a peptide corresponding to this region competitively inhibited the oligomerization of full-length EDEN-BP. Impairing oligomerization by either of these two methods specifically abolished EDEN-dependent deadenylation. Furthermore, impairing oligomerization inhibited the binding of EDEN-BP to its target RNA, demonstrating a strong coupling between EDEN-BP oligomerization and RNA binding.


CONCLUSIONS
These data, showing that the oligomerization of EDEN-BP is required for binding of the protein on its target RNA and for EDEN-dependent deadenylation in Xenopus embryos, will be important for the identification of cofactors required for the deadenylation process.
Cosson
Bertrand
B
CNRS UMR 6061, IFR 140, Université de Rennes 1, Faculté de Médecine, 2 Avenue Léon Bernard, 35043 Rennes Cedex, France.
Gautier-Courteille
Carole
C
Maniey
Dominique
D
Aït-Ahmed
Ounissa
O
Lesimple
Michelle
M
Osborne
H Beverley
HB
Paillard
Luc
L
D000249:Adenosine Monophosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000502:physiology; D004625:Embryo, Nonmammalian; D005260:Female; D008969:Molecular Sequence Data; D011108:Polymers / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D039104:RNA 3' Polyadenylation Signals / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
C110462:EDEN-specific RNA-binding protein, Xenopus; D011108:Polymers; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029867:Xenopus Proteins; D000249:Adenosine Monophosphate