Characterization of the domains of zRICH, a protein induced during optic nerve regeneration in zebrafish.
Teleost fish show a remarkable capability of nerve regeneration in their CNS, while injuries to axon fibers in the CNS of mammals result in degeneration and loss of function. Understanding this difference has biomedical consequences to humans. Both extrinsic factors from the neuronal environment and intrinsic neuronal factors seem to play a role in successful nerve regeneration. Among the intrinsic factors, a number of proteins termed axonal growth associated proteins (GAPs) are strongly induced during axon regeneration. RICH proteins are axonal GAPs that show homology to mammalian myelin marker proteins termed CNPases. Sequence analysis distinguishes three domains in these proteins. In this report, mutant versions of zebrafish RICH proteins were generated to study the roles of the domains of the protein at biochemical and cellular levels. The central CNPase homology domain was sufficient for catalytic activity. The amino terminal acidic domain causes the anomalous electrophoretic migration observed for RICH proteins. The small C-terminal domain bears an isoprenylation motif and is necessary for the interaction of zRICH with cellular membranes. At the cellular level, expression of wild-type zRICH protein in PC12 cells did not induce neurite generation. Additionally, neither the expression of wild-type zRICH nor the expression of mutant versions of the protein interfered with the levels of differentiation of PC12 cells induced by nerve growth factor, suggesting that, at least in this model of neuronal differentiation, zRICH proteins do not participate in the process of generation of neurites.
Challa
Madhavi
M
Department of Chemistry, Texas A&M University-Kingsville, 700 University Boulevard, Kingsville, TX, USA.
Chapa
Gloria R
GR
Govindaraju
Suman
S
González-García
Maribel
M
Ballestero
Rafael P
RP
D000818:Animals; D015153:Blotting, Western; D002384:Catalysis; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007150:Immunohistochemistry; D007700:Kinetics; D009154:Mutation / Q000502:physiology; D009414:Nerve Growth Factors / Q000235:genetics* / Q000502:physiology; D009416:Nerve Regeneration / Q000502:physiology*; D009900:Optic Nerve / Q000502:physiology*; D016716:PC12 Cells; D010957:Plasmids / Q000235:genetics; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D014162:Transfection; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics* / Q000502:physiology
D009414:Nerve Growth Factors; D011994:Recombinant Proteins; D029961:Zebrafish Proteins