In an earlier study, we showed that expressions of GD3, GT1b, and GQ1b gangliosides in P19 embryonic carcinoma (EC) cells were enhanced during their neural differentiation induced by retinoic acid. We now further demonstrated that this increase of the b-series gangliosides is due to an increase in their corresponding synthases (sialyltransferase-II, -IV, and -V) in the Golgi. Of the three gangliosides studied, GQ1b appeared to be the best candidate for monitoring such differentiation process. We also used fluorescence-labeled monoclonal antibodies and confocal fluorescence microscopy to obtain direct visual information about the relationship of gangliosides and neural specific proteins in neuron development. Again, GQ1b is the most interesting as it localizes with synaptophysin and neural cell adhesion molecules (NCAMs) on synaptic boutons or dendritic spines in RA-induced neurons (R/N). This suggests that GQ1b could be used as a marker for synapse formation during construction of the neural network.
