GAP-43 gene expression during development: persistence in a distinctive set of neurons in the mature central nervous system.
GAP-43 is a rapidly transported axonal protein most prominently expressed in regenerating and developing nerves. However, the low level persistence of GAP-43 in the adult CNS where growth and regenerative capacity are minimal may additionally indicate a role for this molecule in neuronal remodeling. Previous studies have revealed GAP-43 immunoreactivity in neurites throughout many regions of the CNS. To identify the CNS neurons that express GAP-43 at different stages of development, we utilized in situ hybridization and immunocytochemistry; the latter was performed with an antibody that recognizes GAP-43 immunoreactivity in both perikarya and neurites. In the perinatal period GAP-43 is expressed in all neurons. Subsequently its expression becomes progressively restricted such that by maturity most neurons no longer express detectable levels, although GAP-43 expression is still moderately high in the adult entorhinal cortex, and strikingly high in the adult hippocampus and olfactory bulb. In light of current notions about the function of GAP-43, it is tempting to speculate that this anatomy denotes neurons engaged in structural remodeling and functional plasticity.
De la Monte
S M
SM
Howard Hughes Medical Institute, Massachusetts General Hospital Cancer Center, Boston 02114.
Federoff
H J
HJ
Ng
S C
SC
Grabczyk
E
E
Fishman
M C
MC
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D005314:Embryonic and Fetal Development; D019922:GAP-43 Protein; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000502:physiology; D009693:Nucleic Acid Hybridization; D051381:Rats; D013116:Spinal Cord / Q000196:embryology / Q000378:metabolism*
D019922:GAP-43 Protein; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins