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|Similar and Divergent Effects of ppGpp and DksA Deficiencies on Transcription in Escherichia coli.
Fernández Vázquez, Jorge
Cabrer Panes, Juan David
Sànchez, Àlex (Sànchez Pla)
Balsalobre Parra, Carlos
|American Society for Microbiology
|The concerted action of ppGpp and DksA in transcription has been widely documented. In disparity with this model, phenotypic studies showed that ppGpp and DksA might also have independent and opposing roles in gene expression in Escherichia coli. In this study we used a transcriptomic approach to compare the global transcriptional patterns of gene expression in strains deﬁcient in ppGpp (ppGpp0) and/or DksA ( dksA). Approximately 6 and 7% of all genes were signiﬁcantly affected by more than twofold in ppGpp- and DksAdeﬁcient strains, respectively, increasing to 13% of all genes in the ppGpp0 dksA strain. Although the data indicate that most of the affected genes were copositively or conegatively regulated by ppGpp and DksA, some genes that were independently and/or differentially regulated by the two factors were found. The large functional group of chemotaxis and ﬂagellum synthesis genes were notably differentially affected, with all genes being upregulated in the DksA-deﬁcient strain but 60% of them being downregulated in the ppGpp-deﬁcient strain. Revealingly, mutations in the antipausing Gre factors suppress the upregulation observed in the DksA-deﬁcient strain, emphasizing the importance of the secondary channel of the RNA polymerase for regulation and ﬁne-tuning of gene expression in E. coli.
|Reproducció del document publicat a: http://dx.doi.org/10.1128/JB.01410-08
|It is part of:
|Journal of Bacteriology, 2009, vol. 191, num. 10, p. 3226-3236
|Appears in Collections:
|Articles publicats en revistes (Genètica, Microbiologia i Estadística)
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