Abstract
The murine genome contains approximately 70 protocadherin (Pcdh) genes. Many are expressed in the nervous system, suggesting that Pcdhs may specify neuronal connectivity. Here, we analyze the 22 contiguous genes of the Pcdh-gamma cluster. Individual neurons express subsets of Pcdh-gamma genes. Pcdh-gamma proteins are present in most neurons and associated with, but not confined to, synapses. Early steps in neuronal migration, axon outgrowth, and synapse formation proceed in mutant mice lacking all 22 Pcdh-gamma genes. At late embryonic stages, however, dramatic neurodegeneration leads to neonatal death. In mutant spinal cord, many interneurons are lost, but sensory and motor neurons are relatively spared. In cultures from mutant spinal cord, neurons differentiate and form synapses but then die. Thus, Pcdh-gamma genes are dispensable for at least some aspects of connectivity but required for survival of specific neuronal types.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Brain / cytology
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Brain / physiology
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Cadherin Related Proteins
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Cadherins / genetics
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Cadherins / metabolism*
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Cell Differentiation / physiology
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Cell Fractionation
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Cell Survival / physiology*
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Cells, Cultured
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Embryo, Mammalian / anatomy & histology
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Embryo, Mammalian / physiology
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Hippocampus / cytology
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Hippocampus / metabolism
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Immunohistochemistry
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In Situ Hybridization
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Interneurons / physiology*
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Interneurons / ultrastructure
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Mice
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Mice, Knockout
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Multigene Family
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Protein Isoforms / genetics
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Protein Isoforms / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Retina / cytology
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Retina / metabolism
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Spinal Cord / cytology*
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Spinal Cord / metabolism
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Spinal Cord / pathology
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Synapses / chemistry
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Synapses / metabolism
Substances
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Cadherin Related Proteins
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Cadherins
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Gamma-protocadherins
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Protein Isoforms
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Recombinant Fusion Proteins