title: RNA-binding profiles ofDrosophilaCPEB proteins Orb and Orb2.
abstract: Localized protein translation is critical in many biological contexts, particularly in highly polarized cells, such as neurons, to regulate gene expression in a spatiotemporal manner. The cytoplasmic polyadenylation element-binding (CPEB) family of RNA-binding proteins has emerged as a key regulator of mRNA transport and local translation required for early embryonic development, synaptic plasticity, and long-term memory (LTM).DrosophilaOrb and Orb2 are single members of the CPEB1 and CPEB2 subfamilies of the CPEB proteins, respectively. At present, the identity of the mRNA targets they regulate is not fully known, and the binding specificity of the CPEB2 subfamily is a matter of debate. Using transcriptome-wide UV cross-linking and immunoprecipitation, we define the mRNA-binding sites and targets ofDrosophilaCPEBs. Both Orb and Orb2 bind linear cytoplasmic polyadenylation element-like sequences in the 3' UTRs of largely overlapping target mRNAs, with Orb2 potentially having a broader specificity. Both proteins use their RNA-recognition motifs but not the Zinc-finger region for RNA binding. A subset of Orb2 targets is translationally regulated in cultured S2 cells and fly head extracts. Moreover, pan-neuronal RNAi knockdown of these targets suggests that a number of these targets are involved in LTM. Our results provide a comprehensive list of mRNA targets of the two CPEB proteins inDrosophila, thus providing insights into local protein synthesis involved in various biological processes, including LTM.
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria; stepien@mpi-cbg.de kelemank@janelia.hhmi.org.
authors: Barbara Krystyna
authors: BK
authors: Stepien
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria.
authors: Cornelia
authors: C
authors: Oppitz
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria.
authors: Daniel
authors: http://orcid.org/0000-0001-9338-3765
authors: D
authors: Gerlach
authors: Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147.
authors: Ugur
authors: U
authors: Dag
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria.
authors: Maria
authors: M
authors: Novatchkova
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria.
authors: Sebastian
authors: S
authors: Krüttner
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria.
authors: Alexander
authors: A
authors: Stark
authors: The Research Institute of Molecular Pathology, 1030 Vienna, Austria; stepien@mpi-cbg.de kelemank@janelia.hhmi.org.|Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147.
authors: Krystyna
authors: K
authors: Keleman
keywords: CLIP; CPEB; Orb2; long-term memory; translation