Impaired synapse elimination during cerebellar development in PKC gamma mutant mice.
PKC gamma is highly expressed in Purkinje cells (PCs) but not in other types of neurons in the cerebellum. The expression of PKC gamma changes markedly during cerebellar development, being very low at birth and reaching a peak around the third postnatal week. This temporal pattern of PKC gamma expression coincides with the developmental transition from multiple to single climbing fiber innervation onto each PC. In adult mutant mice deficient in PKC gamma, we found that 41% of PCs are still innervated by multiple climbing fibers, while other aspects of the cerebellum including the morphology and excitatory synaptic transmission of PCs appear normal. Thus, elimination of multiple climbing fiber innervation appears to be specifically impaired in the mutant cerebellum. We suggest that the developmental role of PKC gamma may be to act as a downstream element in the signal cascade necessary for the elimination of surplus climbing fiber synapses.
Department of Physiology, Jichi Medical School, Tochigi-ken, Japan.
M
M
Kano
K
K
Hashimoto
C
C
Chen
A
A
Abeliovich
A
A
Aiba
H
H
Kurihara
M
M
Watanabe
Y
Y
Inoue
S
S
Tonegawa
D000367:Age Factors; D000818:Animals; D002531:Cerebellum / Q000196:embryology / Q000473:pathology* / Q000502:physiology; D004594:Electrophysiology; D007527:Isoenzymes / Q000235:genetics*; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants; D008854:Microscopy, Electron; D009473:Neuronal Plasticity / Q000502:physiology; D011493:Protein Kinase C / Q000235:genetics*; D011689:Purkinje Cells / Q000166:cytology / Q000648:ultrastructure; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013569:Synapses / Q000502:physiology*
D007527:Isoenzymes; D016194:Receptors, N-Methyl-D-Aspartate; C087857:protein kinase C gamma; D011493:Protein Kinase C