title: A genome-wide screen of CREB occupancy identifies the RhoA inhibitors Par6C and Rnd3 as regulators of BDNF-induced synaptogenesis.
abstract: Neurotrophin-regulated gene expression is believed to play a key role in long-term changes in synaptic structure and the formation of dendritic spines. Brain-derived neurotrophic factor (BDNF) has been shown to induce increases in dendritic spine formation, and this process is thought to function in part by stimulating CREB-dependent transcriptional changes. To identify CREB-regulated genes linked to BDNF-induced synaptogenesis, we profiled transcriptional occupancy of CREB in hippocampal neurons. Interestingly, de novo motif analysis of hippocampal ChIP-Seq data identified a non-canonical CRE motif (TGGCG) that was enriched at CREB target regions and conferred CREB-responsiveness. Because cytoskeletal remodeling is an essential element of the formation of dendritic spines, within our screens we focused our attention on genes previously identified as inhibitors of RhoA GTPase. Bioinformatic analyses identified dozens of candidate CREB target genes known to regulate synaptic architecture and function. We showed that two of these, the RhoA inhibitors Par6C (Pard6A) and Rnd3 (RhoE), are BDNF-induced CREB-regulated genes. Interestingly, CREB occupied a cluster of non-canonical CRE motifs in the Rnd3 promoter region. Lastly, we show that BDNF-stimulated synaptogenesis requires the expression of Par6C and Rnd3, and that overexpression of either protein is sufficient to increase synaptogenesis. Thus, we propose that BDNF can regulate formation of functional synapses by increasing the expression of the RhoA inhibitors, Par6C and Rnd3. This study shows that genome-wide analyses of CREB target genes can facilitate the discovery of new regulators of synaptogenesis.
authors.affiliation: Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Program in Neuroscience, Washington State University, Pullman, Washington, United States of America.
authors.forename: Adam
authors.initials: A
authors.lastname: Lesiak
authors.forename: Carl
authors.initials: C
authors.lastname: Pelz
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ando
authors.forename: Mingyan
authors.initials: M
authors.lastname: Zhu
authors.forename: Monika
authors.initials: M
authors.lastname: Davare
authors.forename: Talley J
authors.initials: TJ
authors.lastname: Lambert
authors.forename: Katelin F
authors.initials: KF
authors.lastname: Hansen
authors.forename: Karl
authors.initials: K
authors.lastname: Obrietan
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Appleyard
authors.forename: Soren
authors.initials: S
authors.lastname: Impey
authors.forename: Gary A
authors.initials: GA
authors.lastname: Wayman
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics* / Q000378:metabolism; D049229:Dendritic Spines / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D055106:Genome-Wide Association Study; D006624:Hippocampus / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D055495:Neurogenesis / Q000235:genetics; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013569:Synapses / Q000235:genetics* / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019208:Brain-Derived Neurotrophic Factor; D002352:Carrier Proteins; D017362:Cyclic AMP Response Element-Binding Protein; C504908:Pard6a protein, rat; D020033:Protein Isoforms; C508706:RND3 protein, rat; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein