dinB_mSTM_ST34

dinB, also known as dinP in certain bacterial species, was initially discovered in 1980. Wagner et al. found that dinB was a DNA polymerase belonging to the γ family and playing a crucial role in translesion DNA synthesis. This polymerase can insert deoxyribonucleoside triphosphates across replication-blocking lesions that could potentially be lethal. Previous studies have also indicated that dinB is conserved across various bacterial species. However, in the case of prokaryotes, the occurrence of natural dinB mutant in pathogenic bacteria and the impact of dinB loss on pathoadaptive evolution remains unaddressed. RNA-seq showed that frameshift dinB had cascading effects on the inner gene expression network. The downregulated genes were significantly enriched for several GO terms related to catalytic activity, cellular anatomical entity and metabolic process. As dinB has not been identified as a metabolic gene or a regulator, we reasoned that a frameshift mutation might disturb parts of the bacterial inner flow that were previously maintained by initially expressed dinB. This was particularly exemplified in flagella-associated genes. Unlike the WT strain, dinB frameshift down-regulated FljB and increased the expression level of FliC. Distinct properties of FliC and FljB flagella contribute to efficient motility towards and on host cell surfaces. A distinct expression pattern might result in the choice of host infection and the difference in immune response. In short, frameshift mutation and deletion of dinB altered the bacterial response to ciprofloxacin(CIP) and restructured the inner regulation network. Single colonies were seeded into LB medium and cultured to ~0.1 of OD600. The bacterial solution containing 0.03125μg/ml CIP was subsequently incubated without shaking at room temperature for 10 min, and a liquid nitrogen flash freezer was used to stop the reaction.