Project description:overexpressing DnaN did not affect the genomic DNA pattern in a strain that replicated form the plasmid origin of replication oriN and is deleted for the endogenous origin of replication oriC
Project description:Hydroxyurea (HU) is thought to primarily target ribonucleotide reductase (RNR), therefore inhibiting the conversion of rNTPs into dNTPs and slowing DNA replication. To understand how Bacillus subtilis responds to HU stress, we performed RNA-seq and Tn-seq.
Project description:Initiation of bacterial DNA replication takes place at the origin of replication (oriC), a region characterized by the presence of multiple DnaA boxes that serve as the binding sites for the master initiator protein DnaA. The absence or failure of DNA replication can result in bacterial cell growth arrest or death. Here, we aimed to uncover the physiological and molecular consequences of stopping replication in the model bacterium Bacillus subtilis. For this purpose, DNA replication was blocked using a CRISPRi approach specifically targeting DnaA boxes 6 and 7, which are essential for replication initiation. We characterized the phenotype of these cells and analyzed the overall changes in the proteome using quantitative mass spectrometry. Cells with arrested replication were elongating and not dividing but showed no evidence of DNA damage response (DDR). Moreover, these cells did not cease translation over time. This study sets the ground for future research on non-replicating but translationally active B. subtilis, which might be valuable for biotechnological applications.
Project description:Hydroxyurea (HU) is thought to primarily target ribonucleotide reductase (RNR), therefore inhibiting the conversion of rNTPs into dNTPs and slowing DNA replication. To understand how Bacillus subtilis responds to HU stress, we performed RNA-seq and Tn-seq. We obtained genes with fitness defects following hydroxyurea treatment over 3 growth periods.
Project description:Initiation of DNA replication requires binding of the initiator protein, DnaA, to specific binding sites in the chromosomal origin of replication, oriC. In low G+C Gram-positive bacteria, the primosomal proteins DnaD and DnaB, in conjunction with loader ATPase DnaI, load the replicative helicase at oriC, and this depends on DnaA. DnaD and DnaB are also required to load the replicative helicase outside of oriC during replication restart, in a DnaA-independent manner. DnaA also binds to many sites around the chromosome, outside of oriC, and acts as a transcription factor at several of these. Using chromatin immunoprecipitation, we found that DnaD and DnaB, but not the replicative helicase, are associated with many of the chromosomal regions bound by DnaA in vivo in Bacillus subtilis. This association was dependent on DnaA and the order of recruitment was the same as that at oriC, but was independent of a functional oriC. The presence of DnaD and DnaB at the secondary (non-oriC) targets of DnaA in the absence of helicase loading indicates a possible role for DnaD and DnaB in modulating the activity of DnaA.
Project description:Identification of the specific WalR (YycF) binding regions on the B. subtilis chromosome during exponential and phosphate starvation growth phases. The data serves to extend the WalRK regulon in Bacillus subtilis and its role in cell wall metabolism, as well as implying a role in several other cellular processes.
