The Interaction Between RNase E And All1338 In Anabaena Sp.PCC 7120

RNA degradosome widely exists in bacteria and plays an important role in RNA metabolism.It has been identified in many bacterial species including Escherichia coli,Bacillus subtilis,etc.The RNA degradosome of Escherichia coli have been extensively investigated.However similar complexes have not been well described in cyanobacteria.A recent study in our laboratory showed that RNase E and PNPase form a ribonuclease in vivo,suggesting the existence of cyanobacterial RNA degradosome.In this study,we aim to explore whether there are other protein components in this complex.Our results indicated that the protein All1338 could be co-precipitated with RNase E from the cell lysate in the co-immonoprecipitation assay using the antibody against RNase E.We further demonstrated that RNase E and All1338 could be co-purified with streptactin resin from the Anabaena cells expressing Streptagged All1338.These facts suggest that Rnase E and All1338 are in a complex in vivo.By Native-PAGE and far-Western blotting,we found that the C-terminal of All1338 and the N-terminal of RNase E are responsible for their interaction.All1338 could specifically bind to RNA,suggesting its role in RNA metabolism.Expression analysis for all1338 using promoter-gfp fusion showed that the gene was significantly up-regulated in developing heterocysts,implying that it is involved in heterocyst differentiation.Overall,it is concluded that All1338,which binds to both RNase E and RNA,is a new component of cyanobacterial dedradosome,and it may play an important role in heterocyst development in Anabaena PCC7120.