Tsavaler L, Penhallow R C, Kam W, Sussman H H
Proc Natl Acad Sci U S A. 1987 Jul;84(13):4529-32. doi: 10.1073/pnas.84.13.4529.
The structure of the human placental alkaline phosphatase gene from normal term placentae was studied by restriction enzyme digestion and Southern blot analysis using a cDNA probe to the gene for the placental enzyme. The DNA digests fall into three distinct patterns based on the presence and intensity of an extra 1.1-kilobase Pst I band. The extra 1.1-kilobase band is present in 9 of 27 placenta samples, and in 1 of these samples the extra band is present at double intensity. No polymorphism was revealed by digestion with restriction enzymes EcoRI, Sma I, BamHI, or Sac I. The extra Pst I-digestion site may lie in a noncoding region of the gene because no correlation was observed between the restriction fragment length polymorphism and the common placental alkaline phosphatase alleles identified by starch gel electrophoresis. In addition, because placental alkaline phosphatase is frequently re-expressed in neoplasms, we examined tissue from ovarian, testicular, and endometrial tumors and from BeWo choriocarcinoma cells in culture. The Pst I-DNA digestion patterns from these cells and tissues were identical to those seen in the normal ovary and term placentae. The consistent reproducible digestion patterns seen in DNA from normal and tumor tissue indicate that a major gene rearrangement is not the basis for the ectopic expression of placental alkaline phosphatase in neoplasia.
利用胎盘碱性磷酸酶基因的cDNA探针，通过限制性内切酶消化和Southern印迹分析，研究了足月正常胎盘组织中人胎盘碱性磷酸酶基因的结构。根据一条额外的1.1千碱基对Pst I条带的有无及强度，DNA消化产物呈现出三种不同的模式。在27个胎盘样本中有9个存在这条额外的1.1千碱基对条带，其中1个样本中该额外条带的强度为正常的两倍。用限制性内切酶EcoRI、Sma I、BamHI或Sac I消化未发现多态性。额外的Pst I消化位点可能位于基因的非编码区，因为在限制性片段长度多态性与淀粉凝胶电泳鉴定的常见胎盘碱性磷酸酶等位基因之间未观察到相关性。此外，由于胎盘碱性磷酸酶在肿瘤中常重新表达，我们检测了卵巢、睾丸和子宫内膜肿瘤组织以及培养的BeWo绒毛膜癌细胞系。这些细胞和组织的Pst I-DNA消化模式与正常卵巢和足月胎盘组织中的模式相同。在正常组织和肿瘤组织的DNA中观察到的一致且可重复的消化模式表明，主要的基因重排不是肿瘤中胎盘碱性磷酸酶异位表达的基础。
