Wejksnora P J, Warner J R
Proc Natl Acad Sci U S A. 1979 Nov;76(11):5554-8. doi: 10.1073/pnas.76.11.5554.
Hybrid cell lines formed by fusion of mouse 3T3 cells and Chinese hamster ovary (CHO) cells resistant to emetine, which have an altered 40S ribosomal protein, are generally sensitive to emetine. From most hybrid lines it was possible to select sublines resistant to emetine. The ribosomal components of three lines were studied: A34, an emetine-sensitive hybrid; A34/R3, an emetine-resistant derivative of A34; and A72, an emetine-sensitive hybrid that did not give rise to emetine-resistant sublines. Genetic and biochemical evidence suggests that in A34 both the mouse emetine sensitivity gene and the hamster emetine resistance gene are active, whereas in A34/R3 only the hamster emetine resistance gene is active and in A72 only the mouse emetine sensitivity gene is active. The ribosomes of all three sublines contained both mouse and hamster RNA, predominantly mouse. However, the 60S subunits had roughly equal amounts of the three mouse and hamster proteins that could be distinguished by two-dimensional electrophoresis, suggesting the association of mouse RNA with hamster ribosomal proteins. The emetine-resistant and emetine-sensitive 40S subunits could be separated by sedimentation in 0.5 M KCl. Resistant subunits contained predominantly mouse RNA, presumably associated with the hamster protein conferring emetine resistance. We conclude that hybrid cells can form hybrid ribosomes and that the amounts of ribosomal RNA and ribosomal protein of each species are not closely coupled.
由小鼠3T3细胞与对吐根碱有抗性的中国仓鼠卵巢(CHO)细胞融合形成的杂交细胞系,其40S核糖体蛋白发生了改变,通常对吐根碱敏感。从大多数杂交系中可以筛选出对吐根碱有抗性的亚系。研究了三个细胞系的核糖体成分:A34,一个对吐根碱敏感的杂交细胞系;A34/R3,A34的一个对吐根碱有抗性的衍生物;以及A72,一个对吐根碱敏感且未产生对吐根碱有抗性亚系的杂交细胞系。遗传和生化证据表明,在A34中,小鼠吐根碱敏感基因和仓鼠吐根碱抗性基因均有活性,而在A34/R3中只有仓鼠吐根碱抗性基因有活性,在A72中只有小鼠吐根碱敏感基因有活性。所有三个亚系的核糖体都含有小鼠和仓鼠的RNA,其中以小鼠RNA为主。然而,60S亚基中可通过二维电泳区分的三种小鼠和仓鼠蛋白质的含量大致相等,这表明小鼠RNA与仓鼠核糖体蛋白有关联。对吐根碱有抗性和敏感的40S亚基可以通过在0.5M KCl中沉降分离。抗性亚基主要含有小鼠RNA,推测与赋予吐根碱抗性的仓鼠蛋白相关。我们得出结论,杂交细胞可以形成杂交核糖体,并且每个物种的核糖体RNA和核糖体蛋白的量并非紧密耦合。