Centriole number and process formation in established neuroblastoma cells and primary dorsal root ganglion neurones

Electron microscopy on serial sections has been used to compare the number and position of centrioles and processes in four neuroblastoma clones and in primary dorsal root ganglion neurones. Studies of Neuro-2a and NB41, as well as further experiments on N18 and N115 confirm that a sizeable percentage of the cells in all four neuroblastoma clones have multiple centrioles (2-12 per cell). No significant differences were seen between the number and arrangement of centrioles in the undifferentiated or differentiated states. In contrast primary dorsal root ganglion neurones, although characterized by multiple processes, exhibit only two centrioles per cell, usually located as a pair on one side of the nucleus. The observation that both dorsal root ganglion neurones, as well as neuroblastoma cells with only two centrioles were capable of multiple process formation suggests that multiple centrioles are not obligatory for multiple process formation. In addition no consistent relationship was seen between the location of the centrioles and the position of the processes casting further doubts on models which assume a direct relation between these characteristics.