Disrupted cortical map and absence of cortical barrels in growth-associated protein (GAP)-43 knockout mice

AUTOR(ES)

Maier, Donna L.

FONTE

The National Academy of Sciences

RESUMO

There is strong evidence that growth-associated protein (GAP-43), a protein found only in the nervous system, regulates the response of neurons to axonal guidance signals. However, its role in complex spatial patterning in cerebral cortex has not been explored. We show that mice lacking GAP-43 expression (−/−) fail to establish the ordered whisker representation (barrel array) normally found in layer IV of rodent primary somatosensory cortex. Thalamocortical afferents to −/− cortex form irregular patches in layer IV within a poorly defined cortical field, which varies between hemispheres, rather than the stereotypic, whisker-specific, segregated map seen in normal animals. Furthermore, many thalamocortical afferents project abnormally to widely separated cortical targets. Taken together, our findings indicate a loss of identifiable whisker territories in the GAP-43 −/− mouse cortex. Here, we present a disrupted somatotopic map phenotype in cortex, in clear contrast to the blurring of boundaries within an ordered whisker map in other barrelless mutants. Our results indicate that GAP-43 expression is critical for the normal establishment of ordered topography in barrel cortex.

Documentos Relacionados

• Levels of the growth-associated protein GAP-43 are selectively increased in association cortices in schizophrenia
• The 43-kDa neuronal growth-associated protein (GAP-43) is present in plasma membranes of rat astrocytes.
• Growth-associated protein GAP-43 is expressed selectively in associative regions of the adult human brain.
• Growth-associated protein GAP-43 and L1 act synergistically to promote regenerative growth of Purkinje cell axons in vivo
• Altered phosphorylation of growth-associated protein B50/GAP-43 in Alzheimer disease with high neurofibrillary tangle density.