Transcription attenuation in response to the availability of a specific amino acid is believed to be controlled by alternative configurations of RNA secondary structures that lead to the arrest of translation or the release of the arrested ribosome from the leader mRNA molecule.In this study,we first report a possible example of the DnaA‐dependent riboswitch for transcription attenuation in Escherichia coli.We show that(i)DnaA regulates the transcription of the structural genes but not that of the leader hisL gene;(ii)DnaA might bind to rDnaA boxes present in the HisL‐SL RNA,and subsequently attenuate the transcription of the operon;(iii)the HisL‐SL RNA and rDnaA boxes are phylogenetically conserved and evolutionarily important;and(iv)the translating ribosome is required for deattenuation of the his operon,whereas tRNA^(His) strengthens attenuation.This mechanism seems to be phylogenetically conserved in Gram‐negative bacteria and evolutionarily important.
Staphylococcus lugdunensis(S.lugdunensis)is a coagulase-negative Staphylococcus comprising the normal skin microbiota,primarily colonizing the lower abdomen and extremities.[1]S.lugdunensis has attracted substantial attention in recent years since the discovery of lugdunin by Zipperer et al[2]in 2016.Lugdunin is a secondary metabolite synthesized by non-ribosomal peptide synthetase(NRPS)that inhibits the growth of various grampositive bacteria,including methicillin-resistant S.aureus(MRSA),[2]suggesting its potential as an antibiotic.
In a recent study published in Nature,Levo et al.reported that paralogous genes separated by long distances are regulated by specialized DNA stretches called tethering elements,which enable their physical associations and co-dependent transcriptional coupling during Drosophila embryogenesis.
The phosphoenolpyruvate(PEP):carbohydrate phosphotransferase system(PTS)is widely used by bacteria to take up sugars or sugar derivatives;.PTS is usually composed of a histidine protein(HPr),enzyme I(EI),and several enzyme II(EII)proteins,such as EIIA,EIIB,EIIC,and EIID[1].
ZHANG Yi QuanMA Li ZhiGAO YueQIN QinLI JieLOU JingZHANG Miao MiaoXUE Xing FanKAN BiaoGAO He