Microbial genome analysis and its functional genomics

Since a double helix model of nucleic acid structure appeared, nucleotide sequences have been the focus of biologists' attention as molecular biology has developed. After the Nobel prize for sequencing technique by Sanger and Gilbert, nucleotide sequencing has been gradually improving and finally burst into an era of massive decoding. Present-day, for most biology targets, it has become essential to have their own sequence information to analyze and breed each biological material. Particularly in microbiology fields, genetic strategy was fundamentally reformed and a new field, 'genome microbiology', has been born. The significance of one-nucleotide difference is more and more meaningful, and many past ambiguous results have been clearly elucidated by disclosing whole genome sequences. Here I present some unique techniques using next generation sequencer (NGS) and apply them to determining the bacterial origin of replication. For the analysis of the cyanobacterial study in which basic biological principle, i.e. DNA replication or transcription, has not been elucidated, NBS has been powerful tool and I introduce light-dependent DNA replication as well as DnaA dependency among various cyanobacteria. Alternatively, several newly identified networks involved in essential lipid synthetic enzyme, PlsX, in Bacillus subtilis are described. Based on our post-genome project, we identified several interactions between PlsX and cell division machinery. Besides, from the temperature sensitive mutant of plsX, we obtained many suppressor mutants and therefore analyzed functional interactions among these genes. These analyses revealed the global cellular function which, especially during transient growth phase, senses nutritional availability and regulates cell growth and divisions. It is important to describe cellular rational and intelligent functions at the level of molecular mechanisms.