Chevalier Clément, Huntzinger Eric, Fechter Pierre, Boisset Sandrine, Vandenesch François, Romby Pascale, Geissmann Thomas
Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France.
Methods Enzymol. 2008;447:309-27. doi: 10.1016/S0076-6879(08)02216-7.
Staphylococcus aureus ribonuclease III (Sa-RNase III) belongs to the enzyme family known to process double-stranded RNAs consisting of two turns of the RNA helix. Although the enzyme is thought to play a role in ribosomal RNA processing and gene regulation, the deletion of the rnc gene in S. aureus does not affect cell growth in rich medium. S. aureus RNase III acts in concert with regulatory RNAIII to repress the expression of several mRNAs encoding virulence factors. The action of the RNase is most likely to initiate the degradation of repressed mRNAs leading to an irreversible repression. In this chapter, we describe the overexpression and purification of recombinant RNase III from S. aureus, and we show that its biochemical properties are similar to the orthologous enzyme from Escherichia coli. Both enzymes similarly recognize and cleave different RNA substrates and RNA-mRNA duplexes.
金黄色葡萄球菌核糖核酸酶III（Sa-RNase III）属于已知可加工由两圈RNA螺旋组成的双链RNA的酶家族。尽管该酶被认为在核糖体RNA加工和基因调控中发挥作用，但在金黄色葡萄球菌中缺失rnc基因并不影响其在丰富培养基中的细胞生长。金黄色葡萄球菌核糖核酸酶III与调控性RNAIII协同作用，以抑制几种编码毒力因子的mRNA的表达。核糖核酸酶的作用很可能引发被抑制mRNA的降解，导致不可逆的抑制。在本章中，我们描述了从金黄色葡萄球菌中重组核糖核酸酶III的过表达和纯化，并表明其生化特性与来自大肠杆菌的直系同源酶相似。两种酶同样能识别并切割不同的RNA底物和RNA-mRNA双链体。
