Pfahl M, Kelleher R J, Bourgeois S
Mol Cell Endocrinol. 1978 Apr;10(2):193-207. doi: 10.1016/0303-7207(78)90125-9.
Some general features of dexamethasone resistance in five murine lymphoid cell lines were investigated. To obtain large numbers of dexamethasone-resistant (Dexr) variants, a technique was developed by which mouse lymphoid cell lines can be grown with high efficiency on the surface of agar plates without a feeder layer. A total of 271 Dexr variants were investigated, and 90% of them turned out to lack detectable steroid receptor whereas 10% have receptor with, in most cases, a normal affinity for the steroid hormone. Most of this latter class of variants, however, have reduced amounts of receptor and the receptor of all of them displayed altered nuclear binding characteristics. None of the five investigated lymphoid cell lines yielded a Dexr variant with a normal receptor. These results confirm the idea that the high incidence of receptor variant may be due, at least in part, to the haploid state of a gene coding for the receptors. In cell fusion experiments it could be shown that Dexs is dominant over Dexr, but that a Dexr a-lele in a tetraploid cell can lead to an increased frequency of steroid resistance.
研究了五种小鼠淋巴细胞系中地塞米松耐药性的一些一般特征。为了获得大量地塞米松耐药（Dexr）变体，开发了一种技术，通过该技术小鼠淋巴细胞系可以在没有饲养层的琼脂平板表面高效生长。共研究了271个Dexr变体，其中90%被证明缺乏可检测到的类固醇受体，而10%具有受体，在大多数情况下，该受体对类固醇激素具有正常亲和力。然而，后一类变体中的大多数受体数量减少，并且它们所有的受体都表现出改变的核结合特性。所研究的五个淋巴细胞系中没有一个产生具有正常受体的Dexr变体。这些结果证实了这样一种观点，即受体变体的高发生率可能至少部分归因于编码受体的基因的单倍体状态。在细胞融合实验中可以表明，Dexs对地塞米松耐药是显性的，但四倍体细胞中的Dexr等位基因可导致类固醇耐药频率增加。
