Miskin R, Soreq H
Nucleic Acids Res. 1981 Jul 24;9(14):3355-63. doi: 10.1093/nar/9.14.3355.
Induction of synthesis of the protease plasminogen activator (PA) by hormones, oncogenic viruses and tumor promoters occurs at the transcription level. A novel bioassay for PA messenger RNA was developed to study the regulation of PA synthesis and the genetic elements involved in it. Poly(A)-containing RNA from HEp-3, a PA-rich tumor of human origin, was found to direct the synthesis of a new proteolytic activity when microinjected into Xenopus oocytes. Newly synthesized protease can be detected within a few hours after microinjection of minute quantities of unfractionated mRNA. The new enzymatic activity is indistinguishable from human PA: it is absolutely dependent on human plasminogen; it is neutralized by serum raised against urokinase, the human urinary PA; and it comigrates with urokinase and HEp-3 PA in gel electrophoresis, exhibiting a molecular weight of 60,000.
激素、致癌病毒和肿瘤启动子对蛋白酶纤溶酶原激活剂（PA）合成的诱导发生在转录水平。为了研究PA合成的调控及其相关的遗传元件，开发了一种新的PA信使核糖核酸生物测定法。当将来自富含PA的人源肿瘤HEp-3的含聚腺苷酸（Poly(A)）RNA微量注射到非洲爪蟾卵母细胞中时，发现它能指导一种新的蛋白水解活性的合成。在微量注射微量未分级的信使核糖核酸后数小时内就能检测到新合成的蛋白酶。这种新的酶活性与人类PA无法区分：它绝对依赖于人类纤溶酶原；它被针对人尿PA尿激酶产生的血清中和；并且它在凝胶电泳中与尿激酶和HEp-3 PA共迁移，分子量为60,000。
