| Research Abstract |
We showed previously that introduce of the cDNA encoding GD3 synthase into mouse neuroblastoma Neuro2a cells led to convert surface major gangliosides of the cells from GM1 and GD1a to GD3 and GQ1b, and subsequently cell were differentiated with neurite sprouting.
To gain a better understanding of consequences of GD3 synthase expressing in Neuro2a cells and explain the possible mechanism responsible for the Neuro2a morphological change, we first search the regulatory expression systems for sialyltransferase. We found that the recent developed tetracycline regulated system was suitable to control expression of sialyltransferase cDNA.Then, we applied this system to Neuro2a cells and GD3 synthase cDNA.Under this system, Neuro2a was differentiated into cholinergic-like neuronal cells with neurite sprouting 20 days after induction of GD3 synthase, although GD3 synthase mRNA was expressed 4 h after induction and kept at a low level during the process. Recently, we have identified several gene
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s that were involved this differentiation process by differential display method. Now we are analyzing these new genes.
To examine the importance of cell surface gangliosides for neural cell morphology and cellular functions, cDNA encoding alpha1,2-fucosyltransferase was introduced into Neuro2a cells. After transfection of the cDNA,the cells expressed fucosyl-GM1 as the major ganglioside. It is known that Neuro2a cells sprout a axon-like neurite under serum free condition. However, fucosyltransferase cDNA-transfected cells sprout several dendrite-like neurites under serum-free condition. This phenomenon was revered by removing of fucosyl-GM1 from cell surface.
Our results strongly suggest that cell surface gangliosides play a role for neuronal cell behavior and differentiation. In addition, stable transfection of the glycosyltransferases into cells, particularly under regulated system, is a good approach for analyzing of the functions of gangliosides and subsequent signal transduction mechanisms in neuronal cells. Less
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