Benedict W F, Nebert D W, Thompson E B
Proc Natl Acad Sci U S A. 1972 Aug;69(8):2179-83. doi: 10.1073/pnas.69.8.2179.
Aryl hydrocarbon hydroxylase activity is inducible in mouse 3T3 fibroblasts by benz[alpha]anthracene, whereas no detectable basal or inducible levels of this enzyme occur in rat-hepatoma tissue culture cells. Conversely, tyrosine aminotransferase activity is inducible in hepatoma cells by dexamethasone, whereas only low noninducible levels of this enzyme exist in 3T3 cells. In hybrids formed by fusion of these two parent lines, levels of inducible hydroxylase activity range from the same as, to more than 20-fold greater than, that in the 3T3 parent; aminotransferase levels remain very low and noninducible in all of these same hybrids. A majority of the 1S-chromosomal complement from each parent is retained in most of these hybrids. The kinetics of hydroxylase induction and degradation, responses of hydroxylase induction to actinomycin D and cycloheximide, and the relative thermolability of the control and induced activities are similar in the 3T3 parent and in the hybrids. Failure to inactivate any of the aminotransferase activity in the hybrids with antibody specific for the rat enzyme indicates that all of the basal noninducible aminotransferase activity is derived from the mouse 3T3 parent.
苯并[a]蒽可诱导小鼠3T3成纤维细胞中的芳烃羟化酶活性，而在大鼠肝癌组织培养细胞中未检测到该酶的基础水平或诱导水平。相反，地塞米松可诱导肝癌细胞中的酪氨酸转氨酶活性，而在3T3细胞中仅存在低水平的非诱导性该酶。在由这两个亲本品系融合形成的杂种细胞中，诱导型羟化酶活性水平与3T3亲本中的水平相同，或比其高20倍以上；在所有这些杂种细胞中，转氨酶水平仍然非常低且不可诱导。在大多数这些杂种细胞中，每个亲本的大部分1S染色体互补体得以保留。3T3亲本和杂种细胞中羟化酶诱导和降解的动力学、羟化酶诱导对放线菌素D和环己酰亚胺的反应，以及对照和诱导活性的相对热稳定性相似。用针对大鼠酶的特异性抗体未能使杂种细胞中的任何转氨酶活性失活，这表明所有基础非诱导性转氨酶活性均来自小鼠3T3亲本。
