RNase E is an endoribonuclease and plays a central role in RNA metabolism. Cyanobacteria, as ancient oxygen-producing photosynthetic bacteria, also contain RNase E homologues. Here, we introduced mutations into the S1 subdomain (F53A), the 5′-sensor subdomain (R160A), and the DNase I subdomain (D296A) according to the key activity sites of Escherichia coli RNase E. The results of degradation assays demonstrated that Asp296 is important to RNase E activity in Anabaena sp. PCC 7120 (hereafter PCC 7120). The docking model of RNase E in PCC 7120 (AnaRne) and RNA suggested a possible recognition mechanism of AnaRne to RNA. Moreover, overexpression of AnaRne and its N-terminal catalytic domain (AnaRneN) in vivo led to the abnormal cell division and inhibited the growth of PCC 7120. The quantitative analysis showed a significant decrease of ftsZ transcription in the case of overexpression of AnaRne or AnaRneN and ftsZ mRNA could be directly degraded by AnaRne through degradation assays in vitro, indicating that AnaRne was related to the expression of ftsZ and eventually affected cell division. In essence, our studies expand the understanding of the structural and functional evolutionary basis of RNase E and lay a foundation for further analysis of RNA metabolism in cyanobacteria.

RNase E是一种核糖核酸内切酶，在RNA代谢中起着核心作用。蓝细菌作为古老的产生氧气的光合细菌，也含有RNase E同源物。在这里，我们根据大肠杆菌RNase E的关键活性位点将突变引入了S1子域（F53A），5'-传感器子域（R160A）和DNase I子域（D296A）。降解试验的结果表明， Asp296是在核糖核酸酶E活性重要的鱼腥藻。PCC 7120（以下称为PCC 7120）。RNase E在PCC 7120（AnaRne）和RNA中的对接模型表明AnaRne对RNA的可能识别机制。此外，体内的AnaRne及其N末端催化结构域（AnaRneN）过表达导致细胞分裂异常并抑制PCC 7120的生长。定量分析显示，在AnaRne或AnaRneN过​​表达的情况下，ftsZ转录显着降低，并且AnaRne可以通过体外降解试验直接降解ftsZ mRNA 。 AnaRne与ftsZ的表达有关，并最终影响细胞分裂。从本质上讲，我们的研究扩展了对RNase E的结构和功能进化基础的理解，并为进一步分析蓝细菌中的RNA代谢奠定了基础。