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

1.糖皮质激素调节的ras癌基因对PC12细胞糖脂组成和致瘤性的影响本研究建立了糖皮质激素调节的ras癌基因表达的PC12细胞克隆细胞系，并研究了糖脂组成与细胞分化的关系。(1)将地塞米松(DX)调控的人c-Ha-ras癌基因导入PC12细胞，建立了转染性细胞系MR31。(2)加入DX后，MR31细胞突起突起增多，儿茶酚胺含量增加。(3)神经节苷脂含量在PC12和MR31之间没有变化，但在MR31-DX中神经节苷脂含量增加到MR31的2倍，并且PC12和MR31的组成不同。(4)中性糖脂的组成在MR31和MR31-DX之间保持不变，但在PC12和MR31之间有所不同：在MR31中，极性组分比Gal-Cth显著减少。(5)检测ras基因转导对裸鼠成瘤的影响。在PC12细胞系中，肿瘤在30天内生长，35天后直径至少达到10 mm。相反，在与PC12相同的条件下，MR31和ME31-DX的成瘤率较低：这两种细胞株的潜伏期更长，体积更小。羟脑苷脂基因在NIH3T3细胞中的表达这项研究仍在进行中。

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.