title: The relationship between PSD-95 clustering and spine stability in vivo.
abstract: The appearance and disappearance of dendritic spines, accompanied by synapse formation and elimination may underlie the experience-dependent reorganization of cortical circuits. The exact temporal relationship between spine and synapse formation in vivo remains unclear, as does the extent to which synapse formation enhances the stability of newly formed spines and whether transient spines produce synapses. We used in utero electroporation of DsRedExpress- and eGFP-tagged postsynaptic density protein 95 (PSD-95) to investigate the relationship between spine and PSD stability in mouse neocortical L2/3 pyramidal cells in vivo. Similar to previous studies, spines and synapses appeared and disappeared, even in naive animals. Cytosolic spine volumes and PSD-95-eGFP levels in spines covaried over time, suggesting that the strength of many individual synapses continuously changes in the adult neocortex. The minority of newly formed spines acquired PSD-95-eGFP puncta. Spines that failed to acquire a PSD rarely survived for more than a day. Although PSD-95-eGFP accumulation was associated with increased spine lifetimes, most new spines with a PSD did not convert into persistent spines. This indicates that transient spines may serve to produce short-lived synaptic contacts. Persistent spines that were destined to disappear showed, on average, reduced PSD-95-eGFP levels well before the actual pruning event. Altogether, our data indicate that the PSD size relates to spine stability in vivo.
authors: Department of Basic Neurosciences, Faculty of Medicine and the Geneva Neuroscience Center, University of Geneva, CH 1211, Switzerland, and Lemanic Neuroscience Doctoral School, Biological Electron Microscopy Facility, Centre of Electron Microscopy, and Computer Vision Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, CH 1015, Switzerland.
authors: Michele
authors: M
authors: Cane
authors: Bohumil
authors: B
authors: Maco
authors: Graham
authors: G
authors: Knott
authors: Anthony
authors: A
authors: Holtmaat
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D049229:Dendritic Spines / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure*; D000076122:Disks Large Homolog 4 Protein; D005260:Female; D051528:Guanylate Kinases / Q000032:analysis* / Q000502:physiology / Q000648:ultrastructure*; D008297:Male; D008565:Membrane Proteins / Q000032:analysis* / Q000502:physiology / Q000648:ultrastructure*; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy
chemical_list: D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; D008565:Membrane Proteins; D051528:Guanylate Kinases