Protein-protein interaction network supporting growth and differentiation of Bacillus subtilis

点击翻译按钮获取中文摘要

1) We newly constructed about 300 mutants of the genes identified by genome sequencing, to complete the international mutant construction project, and reported that 271 genes are essential for the B. subtilis growth at 37℃ in LB medium.2) Among essential genes without known function, we have found that yacA encodes an RNA-modifying enzyme responsible for lysidine formation and yneS, together with plsX, is essential for the first step of phospholipids biosynthesis. In addition, one of the essential GTP binding proteins, YlqF, has been demonstrated to participate in the last step of 50S ribosome subunit assembly.3) We have attempted to construct knock out mutant of each of 57 ribosome protein genes, and found that 22 are dispensable for the growth.4) We have systematically analyzed the synthetic lethality of double knockout of paralogous gene pairs, and found that the polA-yacP double mutant is lethal due to the defect in removal of primer RNA of Okazaki fragments.5) By combination of proteome, transcriptome and genetic analysis, in addition to 119 genes previously reported, we have newly identified 175 genes that are expressed specifically during sporulation, and determined sigma factors responsible for their expression. We have also analyzed the localization of GFP fusions of about 90 spore proteins, and found at least 10 different the localization patterns.6) We have attempted the analysis of protein-protein interaction network by using yeast two-hybrid analysis and mass spectroscopic analysis of in vivo protein complex, and identified several interesting interactions; anti-sigma proteins regulating activities of ECF sigma factors, Rap proteins regulating ComK responsible for competence development, YheIH involved in regulation of phosphor-relay inducing initiation of sporulation, YlqF interacting with FtsZ and involved in cell division, and YabA interacting with DnaA and DnaA and regulating initiation of genome replication.