Upregulation of a New Microglial Gene, mrf-1, in Response to Programmed Neuronal Cell Death and Degeneration

摘要: Cerebellar granule neurons isolated from postnatal day 7 (P7) rats and grown in normal K+ medium begin to degenerate at approximately 4 d vitro (DIV) die. To search for genes upregulated the process of neuronal cell death, differential hybridization was performed with subtracted cDNA probes a library 5 DIV. One microglial response factor-1 (mrf-1), which encoded sequence 177 amino acids single EF-hand calcium-binding motif. By Northern blots, transcript cerebellar culture DIV, peaked 6 decreased Upregulation also found when apoptosis cells induced by replacing high medium. However, non-neuronal were thoroughly eliminated aphidicolin, an antimitotic agent, upregulation 4-7 DIV did not occur. immunocytochemistry, MRF-1 detected OX-42-positive (microglia), it exhibited increase death. levels microglia purified cerebral cortex presence cells. In developing cerebellum vivo, mrf-1 mRNA transiently increased early stages, reaching peak P7 astrocytes undergo extensive apoptosis. adult brain sections, perikarya processes ramified/resting microglia, peripheral motor nerve dissection prominently expression activated surrounding injured central motoneurons. Therefore, appears be one that respond death degeneration.