Donovan W P, Kushner S R
Nucleic Acids Res. 1983 Jan 25;11(2):265-75. doi: 10.1093/nar/11.2.265.
A 7.1 kb HindIII-XhoI fragment of E. coli DNA which contains the structural gene for ribonuclease II (rnb) has been cloned in the recombinant plasmid pDK24. At least two constitutively expressed genes are encoded on the fragment as shown by maxicell analysis. On denaturing polyacrylamide gels RNase II appears as a single 72,000 dalton species. The approximate site of transcription initiation of the rnb gene has been mapped. Although derivatives of E. coli harboring pDK24 contained 10-fold more RNase II activity that wild type strains without the plasmid, the degradation rate of mRNA was similar in all strains tested. Strains deficient in both RNase II and polynucleotide phosphorylase appear inviable.
一段包含核糖核酸酶II（rnb）结构基因的7.1 kb大肠杆菌DNA的HindIII - XhoI片段已克隆到重组质粒pDK24中。如大细胞分析所示，该片段上至少编码了两个组成型表达的基因。在变性聚丙烯酰胺凝胶上，核糖核酸酶II表现为单一的72,000道尔顿条带。已确定rnb基因转录起始的大致位点。尽管携带pDK24的大肠杆菌衍生物的核糖核酸酶II活性比不含该质粒的野生型菌株高10倍，但在所有测试菌株中，mRNA的降解速率相似。核糖核酸酶II和多核苷酸磷酸化酶均缺陷的菌株似乎无法存活。
