Section: Figures

Joel Richter, Ph.D.

Academic Role: Professor

Faculty Appointment(s) In:
   Program in Molecular Medicine

Other Affiliation(s):
   Interdisciplinary Graduate Program
   Program in Neuroscience

Figure

Translational Control during the Embryonic Cell Cycle. During S-phase, cyclin B1 RNA is dormant and contains a short poly(A) tail. Within the 3' untranslated region of this RNA are two key cis elements, the CPE (cytoplasmic polyadenylation element) and the AAUAAA hexanucleotide. The CPE is bound by CPEB, which in turn is bound by Maskin, which in turn is bound by eIF4E, the cap-binding factor. The cleavage and polyadenylation specificity factor (CPSF) maybe loosely associated with the AAUAAA. As cells enter mitosis (M-phase), Aurora phosphorylates CPEB serine 174, which causes CPEB to bind and recruit CPSF and poly(A) polymerase (PAP) into an active cytoplasmic polyadenylation complex. PAP catalyzes poly(A) elongation, and as a consequence poly(A) binding protein (PABP) is attracted to the RNA. PABP then associates with eIF4G, which together displace Maskin from eIF4E. eIF4G, through eIF3, brings the 40s ribosomal subunit to the RNA and promotes translation initiation. As cells leave M-phase, a hypothetical phosphatase dephosphorylates CPEB, which causes deadenylation, the reasssociation of Maskin with eIF4E, and translational silencing.

Office: Biotech 2 Suite 204
Phone: 508-856-8615
E-mail: Joel.Richter@umassmed.edu
Keywords: Neurobiology, Gene Expression, Developmental Biology

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