Polyoma mutants that productively infect F9 embryonal carcinoma cells do not rescue wild-type polyoma in F9 cells.
Polyoma mutants that productively infect F9 embryonal carcinoma cells do not rescue wild-type polyoma in F9 cells.
复制标题
有效感染 F9 胚胎癌细胞的多瘤突变体不能拯救 F9 细胞中的野生型多瘤。
DOI：
10.1073/pnas.79.5.1479
复制
发表时间：
1982
影响因子：
11.1
通讯作者：
Linney,E
中科院分区：
文献类型：
--
作者：
Fujimura,FK;Linney,E
小鼠胚胎癌细胞对野生型多瘤病毒的感染很难抵抗，感染过程显然在吸附和渗透后但在早期蛋白质合成之前的阶段被阻止。已经分离出能够生产性感染小鼠胚胎癌细胞的多瘤病毒突变体，这些突变体在病毒基因组复制起点附近的非编码区都具有DNA序列改变。PyF 101和PyF 441是两种选择的突变体，它们能够感染胚胎癌细胞系F9。在这里，我们表明，这些PyF突变体不救援复制的野生型多瘤病毒在混合感染的F9细胞。突变体和野生型DNA的基础上，通过与MspI或BstNI消化获得的限制性片段进行区分，并没有野生型DNA被检测到在F9细胞与野生型多瘤病毒和PyF 101或PyF 441共感染。突变病毒在混合感染期间似乎不抑制野生型复制，因为突变和野生型DNA都可以在共感染的3 T6细胞中有效复制，所述共感染的3 T6细胞允许突变和野生型病毒。构建了在多瘤大肿瘤抗原中具有PyF 101突变和ts-25 E温度敏感突变的双突变体，并发现其对于在F9细胞中的复制是温度敏感的。这种双突变体，命名为PyFts-1，可以在限制性温度下通过与PyF 441共感染在F9细胞中被拯救。这些结果表明，PyF突变影响F9细胞中的两个过程，一个涉及多瘤早期基因的表达，第二个涉及病毒DNA复制。
Mouse embryonal carcinoma cells are refractory to infection by wild-type polyoma virus, the infection process apparently being blocked at a stage after adsorption and penetration but before early protein synthesis. Polyoma virus mutants capable of productive infection of mouse embryonal carcinoma cells have been isolated and these mutants all have DNA sequence alterations in a noncoding region near the origin of replication of the viral genome. PyF101 and PyF441 are two mutants selected for their ability to infect the embryonal carcinoma cell line F9. Here we show that these PyF mutants do not rescue replication of wild-type polyoma during a mixed infection of F9 cells. The mutant and wild-type DNAs were distinguished on the basis of restriction fragments obtained by digestion withMspI orBstNI, and no wild-type DNA was detected in F9 cells coinfected with wild-type polyoma and with either PyF101 or PyF441. The mutant viruses do not appear to inhibit wild-type replication during a mixed infection because both mutant and wild-type DNAs can replicate efficiently in coinfected 3T6 cells which are permissive for both mutant and wild-type viruses. A double mutant having the PyF101 mutation and the ts-25E temperature-sensitive mutation in polyoma large tumor antigen was constructed and found to be temperature-sensitive for replication in F9 cells. This double mutant, designated PyFts-1, can be rescued in F9 cells at the restrictive temperature by coinfection with PyF441. These results suggest that the PyF mutations affect two processes in F9 cells, one involving expression of polyoma early genes and a second involving viral DNA replication.