|Budget Amount *help
¥13,200,000 (Direct Cost : ¥13,200,000)
Fiscal Year 1999 : ¥4,200,000 (Direct Cost : ¥4,200,000)
Fiscal Year 1998 : ¥4,200,000 (Direct Cost : ¥4,200,000)
Fiscal Year 1997 : ¥4,800,000 (Direct Cost : ¥4,800,000)
In all attempt to identify α 2, 3-sialyltransferase involved in synthesis of monosialosyl galactosyl globoside (MSGG), the first substance of globo-series ganglioside, associated with the malignant progression of human renal cell carcinoma (RCC), we utilized both expression cloning procedure and PCR method. Thus far, we could not obtain α 2, 3-sialyltransferase by expression cloning procedure, but 5' precursor of rRNA, placental transforming growth factor β, unknown cDNA, etc. were identified as concentrated cDNA by this procedure. We are now investigating the relationship between these cDNA and expression of MSGG.We obtained hST3Gal I and hST3Gal IV by PCR method. By Northern analysis, there was no clear correlation between hST3Gal I and the malignant progression of human RCC.None of the stable transfectants with hST3Gal I examined showed expression of MSGG.Stable transfectant with hST3Gal IV showed moderate increase of MSGG.However, hST3Gal IV transcript increased prominently in almost all normal renal tissues and decreased in most cases of cancer tissues. It was suggested that hST3Gal IV is associated with renal differentiation. From these results, it was anticipated that there is another a 2, 3-sialyltransferase determining the sysnthesis of MSGG.Investigation of this putative sialyltransferase is still underway. During this research, we identified N-acetyl-galactosaminyl disialosyl typel chain paragloboside (GalNAc DSPG-1) as a novel ganglioside, and found that DSGG is distributed in cells of mesoderm origin. We also found that expression of MSGG is inversely related to that of GM3 in human RCC.