CEREBELLAR GRANULE CELLS ELABORATE NEURITES BEFORE MITOSIS

Neuronal birth and neurite outgrowth have been regarded as discrete, s equential stages of development. However, we recently found that sympa thetic neuroblasts often elaborate axons before mitosis, in culture [E . Wolf, I.B. Black, E. DiCicco-Bloom, Mitotic neuroblasts determine ne uritic patterning of progeny, J. Comp. Neurol. 367 (1996) 623-635] and in vivo [E. Wolf, I.B, Black, E. DiCicco-Bloom, Central and periphera l neuroblasts elaborate neurites prior to division in vivo and in vitr o, Soc. Neurosci. Abstr. 21 (1995) 785; E. Wolf, I.B. Black, E. DiCicc o-Bloom, Mitotic neuroblasts engage in axonal outgrowth and pathfindin g in vivo, Sec. Neurosci. Abstr. 22 (1996) 525]. Here, we report that cerebellar granule cells often divide with heritable neurites in vitro . Therefore, mitotic CNS precursors, in addition to peripheral neurobl asts, simultaneously undergo proliferation and process formation. Pote ntially, neurites on dividing precursors may allow target fields to in fluence directly the course of neurogenesis. (C) 1997 Elsevier Science B.V.