Phylogenic studies of gene expression of myelin specific glycolipid and proteins.

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1.Alteration in glycolipid composition and tumorigenicity of PC12 cells induced by transfection of gluco-corticoid-regulated ras oncogene.We established a clonal cell line of PC12 cells transfected with glucocorticoid-regulated ras oncogene and examined relationship between the oncogenic ability and glycolipid composition in association with neuronal differentiation of ras transfected PC12 cells. (1)Dexamethazone (DX) regulated human c-Ha-ras oncogene was transfected to PC12 cells, and a transfectant MR31 cell line has been established. (2)MR31 cells showed the outgrowth of neurite-like processes and the increase of catecholamine contents by adding DX into the growth medium. (3)Ganglioside content was constant between PC12 and MR31, but increased to 2-fold that of MR31 in MR31-DX,and the composition was different between PC12 and MR31. (4)Composition of neutral glycolipids was constant between MR31 and MR31-DX, but different between PC12 and MR31: Polar components than GaL-CTH greatly decreased in MR31. (5)The effects of fransfection of ras gene on tumorigenicity were examined on nude mice. In PC12 cell lines the tumors grew within 30 days and attained diameters of at least 10mm after 35 days. In contrast, MR31 and ME31-DX showed a lower incidence of tumor formation under the same conditions as in PC12: These two cell lines had longer latency period and were of a smaller size.2. Expression of hydroxycerebroside in NIH3T3 cells by transfection. This study is still underway.