Bestman JE, Cline HT. The RNA binding protein CPEB regulates dendrite morphogenesis and neuronal circuit assembly in vivo. Proc Natl Acad Sci U S A. 2008 Dec 12. [Epub ahead of print]
Bestman and Cline used their in vivo single-cell electroporation protocol to introduce lissamine-tagged Morpholino antisense oligos into individual optic tectal neurons in stage 46 to 48 albino Xenopus laevis tadpoles. They knocked down expression of cytoplasmic polyadenylation element binding protein 1 (CPEB1), a component of some brain ribonucleoprotein (RNP) granules. CPEB1 binds to RNA that have cytoplasmic polyadenylation elements (CPE) in their 3’-untranslated regions; CPEB1 is estimated by bioinformatics to bind to about 7% of brain mRNAs. Binding of CPEB1 to an mRNA’s CPE represses its translation and regulates microtubule-dependant trafficking. When CPEB1 is phosphorylated, the mRNA can be polyadenylated and translated.
The authors collected time-lapse images of neurons over a period of three days after treatment with either CPEB1-targeted Morpholinos or control Morpholinos. In either treatment the dendritic arbors grew, but the arbors of neurons treated with the CPEB1-targeted Morpholinos had only about two-thirds of the total dendritic branch length of the control-treated neurons. Dendritic arbor elaboration is a hallmark of experience-dependent neural plasticity, so this observation suggests that CPEB1 activity is required for experience-based remodeling of the neural circuitry of the visual system.
Bestman JE, Ewald RC, Chiu SL, Cline HT. In vivo single-cell electroporation for transfer of DNA and macromolecules. Nat Protoc. 2006;1(3):1267-72.