Gene expression for glycosyltransferases in transfected neuroblastoma cells

Abstract

To study regulatory mechanisms of ganglioside biosynthesis, genes for sialyltransferase II (ST2) or acetylgalactosaminyltransferase I (GalNAcT) were transfected into different cell lines of a substrain of murine neuroblastoma F‐11 cells (F‐11A). While complex β‐series ganglioside synthesis is negligible in the parental line, cells transfected with genes for either enzyme express complex gangliosides requiring both enzyme activities. We have used primers specific for each of the two genes to determine the level of gene expression (1) in the parental cells where endogenous ST2 and GalNAcT activities are very low, and (2) in each of the transfected cell lines where both enzyme activities are present and complex gangliosides are synthesized. Transcripts for both ST2 and GalNAcT were amplified from cDNA that was reverse‐transcribed from the parental as well as both transfected cell lines. While some differences in transcript number and size were noted between parental, ST2‐transfected, and GalNAcT‐transfected cells, suggesting some degree of transcriptional control, all the cell lines clearly expressed transcripts for both genes. These results support the view that ST2 and GalNAcT act in a coordinated fashion, perhaps as a multienzyme complex, to catalyze the synthesis of complex gangliosides, and that synthesis of complex β‐series gangliosides in these cells is regulated primarily post‐transcriptionally. Acknowledgements: Supported by NIH R15‐DC05179 to L.N.I, NIH NS‐11853 to R.K.Y, and NIH‐NCRR(RCMI) G12‐RRO8124 to the Border Biomedical Research Center at the University of Texas at El Paso.