Kahn C R, Bertolotti R, Ninio M, Weiss M C
Nature. 1981 Apr 23;290(5808):717-20. doi: 10.1038/290717a0.
Somatic cell hybridization is a valuable tool for investigation the control of gene expression in eukaryotic cells. Studies of hybrid cells, heterokaryons, reconstructed cells and cybrids (cytoplasmic hybrids) have suggested that cytoplasmic factors may be involved in this regulatory process. Unfortunately, studies of this kind usually require that hybrid or modified cells be maintained for some time in a selective environment during which chromosomal losses or other changes may modify the genetic functions of the cells and thus vitiate conclusions about the mechanism of gene regulation. We report here the preparation of cybrids between enucleated mouse fibroblasts (Cl-1-D) and differentiated rat hepatoma cells (Fao) and the use of a combination of histological techniques to identify these modified cells early after fusion without the use of selective media. We found that albumin production in most cybrids was suppressed (extinguished) at 12-20 h after fusion but was restored by 48 h. These results suggest that there is a cytoplasmic factor in the fibroblast which exerts negative control over expression of the albumin gene, but which in the absence of the fibroblast nucleus, is not renewed and therefore short-lived.
体细胞杂交是研究真核细胞基因表达调控的一种有价值的工具。对杂交细胞、异核体、重构细胞和胞质杂种（细胞质杂种）的研究表明，细胞质因子可能参与了这一调控过程。不幸的是，这类研究通常要求杂交或修饰的细胞在选择性环境中维持一段时间，在此期间染色体丢失或其他变化可能会改变细胞的遗传功能，从而使关于基因调控机制的结论无效。我们在此报告去核小鼠成纤维细胞（Cl-1-D）与分化的大鼠肝癌细胞（Fao）之间胞质杂种的制备，以及使用组织学技术组合在融合后早期识别这些修饰细胞而不使用选择培养基的方法。我们发现，大多数胞质杂种中的白蛋白产生在融合后12 - 20小时受到抑制（熄灭），但在48小时恢复。这些结果表明，成纤维细胞中存在一种细胞质因子，它对白蛋白基因的表达施加负调控，但在没有成纤维细胞核的情况下，它不会更新，因此寿命短暂。
