白血病病毒感染的SRSV/3T3细胞系DNA转化机制探讨

A STUDY OF THE TRANSFORMING ACTIVITY OF DNAFROM MURINE LEUKEMIA VIRUS INFECTEDSRSV/3T3 CELL LINE

将SRSV/3T3细胞DNA转染NIH/3T3细胞,转染后17d,实验组出现18个集落,对照组出现4个集落。将实验组集落细胞接种于3只BALB/C裸鼠皮下,全部长成纤维肉瘤。将SRSV/3T3细胞DNA用EcoRI和BamHI酶切电泳,分别应用5种癌基因(v-myc、KJ-ras、v-src、v-sis和e-fos)作Southern印迹和分子杂交。发现SRSV/3T3细胞DNA的BamHI酶切片段与c-fos探针杂交后,在2.2～3.0 kb处出现阳性杂交带。应用c-fos单抗检测转化细胞,细胞核内呈阳性反应。表明SRSV/3T3细胞DNA含有fos样转化基因,在转化细胞内有此基因的过度表达。

The SRSV/3T3 cell line is a malignantly expressed transformed cell line from SRS murine leukemia virus infected NIH/3T3 cells. DNA was extracted from these SRSV/3T3 cells and then used to infect NIH/3T3 cells in vitro. The transfected NIH/3T3 cells were transformed to form cell colonies of round and elliptical shapes. 18 cell colonies appeared in the experimental group, and only 4 cell colonies in the control group (P<0.01) which disappeared after one week. Fibrosarcomas were induced locally in three nude mice by inoculating hypodermally the transformed cells. The weights of the induced fibrosarcomas after inoculation were 1.5, 0.8 and 0.3g on the 20, 24 and 28th days, respectively. DNA from 8ESV/3T3 cells was analysed by BamHI enzyme restriction, agarose gel electrophoresis, Southern blot hybridization with 82P labelled c-fos, v-myc, v-sis, v-src and Ki-raS. The resulted showed that a 2.2-3.0 kb gene fragment which shared the same sequences with c-fos gene was present in SRSV/3T3 cellular DNA. Using the monoclone antibody of c-fos to assay the tumor cells from the induced fibrosarcoma revealed the over-expression of c-fos gene in tumor cells, which further indicated that the DNA of SRSV/3T3 cells contains an over-expressed fos-like gene, The products of the over-expressed fos-like gene may involved in the cellular transformation.