Study Of Regulation For Dnd Transcription And Functional Analysis Of The Universal Stress Protein In Streptomyce Lividans 1326

DNA sulfur modification was initially discoveried in Streptomyce lividans 1326.The gene cluster contains four to five genes.The gene cluster is subjected to DndB for transcriptional regulation.We found that the dnd transcription level can be up-regulated to 2.7 times of the initial status,in which strains were treated by diamide,a type of thiol-oxidant.However,the transcriptional response by diamide was lost when the negative regulator dndB was deleted,suggesting that dnd transcription was activated by oxidant stress.dndB gene might participate in the regulation process.Although the dnd gene cluster is subjected to diamide regulation,survival susceptibility difference was not observed between wild type and dnd^-mutant.It is speculated that there maybe also some other unknown proteins can regulate the dnd transcription.The biotin-labeled DNA affinity purification system was designed to search for the potential regulators.Unexpectedly,universal stress protein?USP?was found to bind DNA.USP belongs to an ancient protein family.USP from different Streptomyces species shares90%similarity,with the highly conserved USP-like domain.In Streptomyces,its physiological function has not been reported yet.The association between cAMP and USP was detected using circular dichroism spectroscopy.The alteration of USP CD spectra was observed when USP was mixed with cAMP,suggesting that USP protein from Streptomyces lividans1326 can bind to cAMP.The usp gene?SLI₇517?was also disrupted.Susceptibility of wild-type and the usp disruption mutant strains to the thiol oxidant,diamide,was analyzed.Tolerance to diamide increased after usp was disrupted.qPCR was conducted to detect the expression differences of glutathione peroxidase gene and thiol peroxidase gene between the wild-type and the usp disruption mutant strain.The transcription level of glutathione peroxidase gene was up-regulated in the usp disruption mutant.Therefore,usp might be involved in the regulation process,that suppresses the transcription of glutathione peroxidase when the bacteria exposed to oxidative environment.