RESUMO
We present here the draft genome sequence of Paracoccus sp. strain 228, isolated from the Gulf of Gdansk in the southern part of the Baltic Sea. The assembly contains 4,131,609 bp in 32 scaffolds.
RESUMO
Gene expression regulation by the stringent response effector, ppGpp, is facilitated by DksA protein; however DksA and ppGpp can play independent roles in transcription. In Escherichia coli, the pArgX promoter which initiates the transcription of four tRNA genes was shown to be inhibited by ppGpp. Our studies on the role of DksA in pArgX regulation revealed that it can stimulate transcription by increasing the binding of RNA polymerase to the promoter and the productive transcription complex formation. However, when DksA is present together with ppGpp a severe down-regulation of promoter activity is observed. Our results indicate that DksA facilitates the effects of ppGpp to drive formation of inactive dead-end complexes formed by RNA polymerase at the ArgX promoter. In vivo, ppGpp-mediated regulation of pArgX transcription is dependent on DksA activity. The potential mechanisms of opposing pArgX regulation by ppGpp and DksA are discussed. pArgX is the first reported example of the promoter stimulated by DksA and inhibited by ppGpp in vitro when an overall inhibition occurs in the presence of both regulators. A dual role is thus proposed for DksA in the regulation of the pArgX promoter activity.
Assuntos
Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , RNA Polimerases Dirigidas por DNA/metabolismo , Ligação Proteica , Iniciação da Transcrição Genética , Transcrição GênicaRESUMO
Here, we present the draft genome sequence ofFlavobacteriumsp. 316, isolated from brackish water of the Gulf of Gdansk, southern Baltic Sea. The assembly contains 3,971,755 bp in 17 scaffolds. The sequence will facilitate postgenomic studies on bacterial stress responses in the challenging habitat of the Baltic Sea.
