Knoll B J, Longley M, Sell S
Tumour Biol. 1986;7(2-3):123-35.
Rat hepatocellular carcinomas and normal liver have been screened for mRNA sequences which are more abundant in the carcinomas than in livers. The screen was done by differential colony hybridization of a cDNA library constructed from the mRNA of a primary tumor induced by diethylnitrosamine (DEN). One cDNA was isolated which hybridizes to a 900 nucleotide mRNA present in abundance in six chemically induced rat hepatomas (both primary and transplantable), but is not detectable in normal adult or fetal (17 day) liver. The nucleotide sequence of this cDNA is identical to that reported by Suguoka et al. for the placental isoenzyme of rat glutathione S-transferase (GST-P) (Nucleic Acids Res. 13:6049). A comparison of the GST-P amino acid sequence with those of two liver GST isoenzymes (Yal and Yc) shows only 26% overall homology; however, this homology is concentrated in three regions of 50%, 68.2% and 34.5%. Genomic blotting experiments show that the overproduction of GST-P mRNA in three Morris hepatomas is not due to amplification of genomic DNA sequences hybridizing with the GST-P cDNA. However, hybridizing sequences are contained on at least 72 kb of genomic DNA, suggesting great complexity of the rat GST-P locus.
已对大鼠肝细胞癌和正常肝脏进行筛选，以寻找在癌组织中比肝脏中更丰富的mRNA序列。筛选是通过对由二乙基亚硝胺（DEN）诱导的原发性肿瘤的mRNA构建的cDNA文库进行差异菌落杂交来完成的。分离出一个cDNA，它与一种900个核苷酸的mRNA杂交，该mRNA在六种化学诱导的大鼠肝癌（原发性和可移植性）中大量存在，但在正常成年或胎儿（17天）肝脏中无法检测到。该cDNA的核苷酸序列与Suguoka等人报道的大鼠谷胱甘肽S-转移酶（GST-P）的胎盘同工酶的序列相同（《核酸研究》13:6049）。将GST-P氨基酸序列与两种肝脏GST同工酶（Yal和Yc）的序列进行比较，总体同源性仅为26%；然而，这种同源性集中在三个区域，分别为50%、68.2%和34.5%。基因组印迹实验表明，三种莫里斯肝癌中GST-P mRNA的过量产生不是由于与GST-P cDNA杂交的基因组DNA序列的扩增。然而，杂交序列包含在至少72 kb的基因组DNA上，这表明大鼠GST-P基因座非常复杂。
