EB病毒基因片段转化细胞的基因定位与移植裸鼠的致瘤性检測

EB病毒是DNA肿瘤病毒,它与人类的两种恶性肿瘤Burkitt氏淋巴瘤和鼻咽癌相关,前者是B淋巴细胞的肿瘤,而后者是低分化的鼻咽上皮癌。用EB病毒基因片段(BamHI W及相邻片段)通过转染的方法已成功地转化Rat-1细胞并接种裸鼠形成移植瘤。用~3H标记的EBV DNA探针与转化细胞染色体作核酸原位杂交,结果显示EB病毒的BamHI W片段与1、8号染色体DNA有同源性。经统计证明W片段定位在这两个染色体上,转化细胞与对照细胞结构及数目上并无明显的差异,但转化细胞DNA合成是对照细胞的5.69倍。转化细胞接种裸鼠形成移植瘤后并可传代。移植存活率达93.3%。随着传代代数的增加,肿瘤增大的速度有加快的倾向,细胞染色体众数逐渐增加,接近三倍体(62)。

Localization of Epstein-Barr Virus Gene in Transformed Cell Induced by EBV Genomic Fragment and Tumorigenic Detection of Transplantable Nude Mice Tumour

Epstein-Barr virus(EBV) is unique among the DNA tumour viruses by virtue of its association with two human malignancies: Burkitt's lymphoma and nasopharyngeal carcinoma(NPC), the former being tumour of B lymphocytes and the latter, encompassing low-differentiated epithelial cells of the nasopharynx. Cells of rat fibroblast cell line(Rat-l) were transfected with EBV-DNA BamHI-W and adjacent fragments by means of calcium precipitation and W_4 cell line was obtained as a high efficient transformed clone. The W_4 cells were examined with chromosomal in situ hybridization techniques with a ~3H-EBV DNA probe. Cytological hybridization showed that the BamHI-W fragment was homologous to at least one region on chromosomes (1, 8) and this result seemed to be very characteristic. ~3H-TdR incoporation into DNA of W_4 cells indicated that DNA synthesis of W_4 cells was 5.69 times that of Rat- 1 cells (control group). The W_4 cells could be inoculated in athymic nude mice (NCstrain) and grow up transplantable tumour, in vivo with a high ransplantable rate of 93.3%. The nude mice were sacrificed when their tumour reached l-2cm and the tumous xcised under sterile conditions for establishment of cell lines. Following the cell passage in nude mice, we have found that the model chromosome number of the sixth passage tumour cell was higher than that of W_4 cell (62 : 42).