Poly(A) Tail Length Is Controlled by the Nuclear Poly(A)-binding Protein Regulating the Interaction between Poly(A) Polymerase and the Cleavage and Polyadenylation Specificity Factor*

AUTOR(ES)

Kühn, Uwe

FONTE

American Society for Biochemistry and Molecular Biology

RESUMO

Poly(A) tails of mRNAs are synthesized in the cell nucleus with a defined length, ∼250 nucleotides in mammalian cells. The same type of length control is seen in an in vitro polyadenylation system reconstituted from three proteins: poly(A) polymerase, cleavage and polyadenylation specificity factor (CPSF), and the nuclear poly(A)-binding protein (PABPN1). CPSF, binding the polyadenylation signal AAUAAA, and PABPN1, binding the growing poly(A) tail, cooperatively stimulate poly(A) polymerase such that a complete poly(A) tail is synthesized in one processive event, which terminates at a length of ∼250 nucleotides. We report that PABPN1 is required to restrict CPSF binding to the AAUAAA sequence and to permit the stimulation of poly(A) polymerase by AAUAAA-bound CPSF to be maintained throughout the elongation reaction. The stimulation by CPSF is disrupted when the poly(A) tail has reached a length of ∼250 nucleotides, and this terminates processive elongation. PABPN1 measures the length of the tail and is responsible for disrupting the CPSF-poly(A) polymerase interaction.

Documentos Relacionados

• Stimulation of poly(A) polymerase through a direct interaction with the nuclear poly(A) binding protein allosterically regulated by RNA
• Translational Silencing of Ceruloplasmin Requires the Essential Elements of mRNA Circularization: Poly(A) Tail, Poly(A)-Binding Protein, and Eukaryotic Translation Initiation Factor 4G
• RNA structure is a critical determinant of poly(A) site recognition by cleavage and polyadenylation specificity factor.
• The influenza virus NS1 protein is a poly(A)-binding protein that inhibits nuclear export of mRNAs containing poly(A).
• Yeast poly(A)-binding protein, Pab1, and PAN, a poly(A) nuclease complex recruited by Pab1, connect mRNA biogenesis to export