Internal promoters of the rpoBC operon of Escherichia coli

Ma, Jian-Chuan; Newman, Andrew; Hayward, Richard S.

doi:10.1007/bf00352538

Cited by 23 publications

(12 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Expression of the relevant RNA polymerase subunits was confirmed by maxicell experiments (data not shown). Since P4 is a weak promoter (19,29), the cloned genes are probably transcribed primarily from the secondary bla (antitet) promoter of pBR322 (32). Different strains, polyploid for rpoC after transformation with any of the four plasmids shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

A missense mutation in the rpoC gene affects chromosomal replication control in Escherichia coli

Petersen

Hansen

1991

J Bacteriol

View full text Add to dashboard Cite

An RNA polymerase mutant with a single-base-pair change in the rpoC gene affects chromosome initiation control. The mutation, which is recessive, is a G to A transition leading to the substitution of aspartate for glycine at amino acid residue 1033 in the RNA polymerase beta' subunit. The chromosome copy number is increased twofold in the mutant at semipermissive growth temperatures (39 degrees C). In a delta oriC strain, in which chromosome initiation is governed by an F replicon, chromosome copy number is not affected. Plasmid pBR322 copy number is also increased in the mutant at 39 degrees C. The mutation causes a more than fivefold increased expression of the dnaA gene at 39 degrees C. It is conceivable that it is this high DnaA concentration which causes the high chromosome copy number and that the mutant RNA polymerase beta' subunit exerts its effect by altering the expression of the dnaA gene. However, other factors must be affected as well to explain why the RNA polymerase mutant can grow in a balanced fashion with a high chromosome concentration. This is in contrast to wild-type cells, which exhibit higher origin concentrations when DnaA protein is overproduced, but in which the overall DNA concentration is only moderately affected.

show abstract

Section: Resultsmentioning

confidence: 99%

A missense mutation in the rpoC gene affects chromosomal replication control in Escherichia coli

Petersen

Hansen

1991

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…rplLp. A variety of experiments have indicated that there may be an internal promoter within the rplJLrpoBC gene cluster for the independent expression of rplL (2,5,8,15,17,28). To assess the strength of this promoter, we fused the rplJ-rplL intercistronic region extending from the HindIII site in rplJ to the EcoRI site in rplL to lacZ.…”

Section: Resultsmentioning

confidence: 99%

“…Initial experiments demonstrated that the genes for the 1B and 1' subunits of RNA polymerase are cotranscribed with at least the rplJ and rplL ribosomal protein genes from a promoter upstream of rplJ (rpUp) (26,33,42). A variety of experiments subsequently suggested that there are also two internal promoters within rplJLrpoBC, one preceding rplL (rplLp) and the other before rpoB (rpoBp) (20,25,26,28,33). In addition, a transcriptional attenuator (atn) was located between rplL and rpoB and accounts for the lower frequency of rpoBC transcription compared with that of rplJL (5,6,14,26).…”

mentioning

confidence: 99%

Relative activities of the transcriptional regulatory sites in the rplKAJLrpoBC gene cluster of Escherichia coli

Ralling¹,

Linn²

1984

J Bacteriol

View full text Add to dashboard Cite

The pattern of transcription of the rplKAJLrpoBC gene cluster of Escherichia coli appears to be complex. At least four different promoters and a transcriptional attenuator have been identified. To compare the relative effect of each of the putative promoters and the attenuator on transcription of these genes, we fused these regulatory sites to lacZ. These transcriptional fusions were constructed on lambda transducing phages so a single copy of each could be stably integrated into the chromosome. The level of ,B-galactosidase in a lysogen of each phage reflects the activity of the transcriptional regulatory site. We find that the promoters preceding rplK (rplKp) and rplJ (rplJp) are indeed the major promoters of this gene cluster. The minor promoter before rplL (rplLp) is much weaker and contributes little to the transcription of the downstream genes. Under these conditions, we find no evidence of a promoter (rpoBp) in the rplL-rpoB intercistronic region. The attenuator (atn) terminates ca. 70o of the transcripts initiated at the promoters preceding it. Although we cannot rule out that some transcripts from rplKp may read through into rplJLrpoBC, we find that rplJp alone is sufficient for high-level expression of these genes.The genes for the subunits of Escherichia coli RNA polymerase are cotranscribed with ribosomal protein genes. The genes for ,B and 13' (rpoB and rpoC) are cotranscribed with at least the L10 and L7/12 ribosomal protein genes (rplL and rplJ, respectively) (26,33,42), whereas the a gene (rpoA) is part of an operon containing four ribosomal protein genes (23). More recently, it has been shown that the gene for a (rpoD) is cotranscribed with the S21 gene (rpsU) and the gene for DNA primase (dnaG) (10).The transcription pattern of the rplKAJLrpoBC gene cluster located at 90 min on the E. coli chromosome is complicated. Initial experiments demonstrated that the genes for the 1B and 1' subunits of RNA polymerase are cotranscribed with at least the rplJ and rplL ribosomal protein genes from a promoter upstream of rplJ (rpUp) (26,33,42). A variety of experiments subsequently suggested that there are also two internal promoters within rplJLrpoBC, one preceding rplL (rplLp) and the other before rpoB (rpoBp) (20,25,26,28,33). In addition, a transcriptional attenuator (atn) was located between rplL and rpoB and accounts for the lower frequency of rpoBC transcription compared with that of rplJL (5,6,14,26). A promoter responsible for the cotranscription of rplK and rplA was identified upstream of rplK (rplKp) (2,15,26,43). Recent S1 nuclease mapping of in vivo transcripts suggests that transcription initiated at rplKp is not necessarily terminated after rplA, but can read through into the rplJL genes (9).To further understand the regulation of this complex operon, we have directly compared the relative effect of these different promoters and the attenuator on rplKAJLrpoBC transcription. These transcriptional regulatory sites were fused, both separately and in combination, to the lacZ gene carried on a lambd...

show abstract

“…The TGn motif probably compensates for a poor Ϫ35 region, while the AT richness contributes to the promoter strength (5,30,33). As for grlRA, a number of other bacterial operons possess internal promoters for supplementary expression of downstream genes (35,58,59). For example, the E. coli rplKAJL-rpoBC operon, which codes for ribosomal proteins L11, L1, L10, and L7/L12, as well as the ␤ and ␤Ј subunits of RNA polymerase, contains two major upstream promoters, rplKp and rplJp, and two minor downstream promoters, rplLp and rpoBp (45).…”

Section: Discussionmentioning

confidence: 99%

Transcriptional Analysis of the grlRA Virulence Operon from Citrobacter rodentium

et al. 2010

View full text Add to dashboard Cite

The locus for enterocyte effacement (LEE) is the virulence hallmark of the attaching-and-effacing (A/E) intestinal pathogens, namely, enteropathogenic Escherichia coli, enterohemorrhagic E. coli, and Citrobacter rodentium. The LEE carries more than 40 genes that are arranged in several operons, e.g., LEE1 to LEE5. Expression of the various transcriptional units is subject to xenogeneic silencing by the histone-like protein H-NS. The LEE1-encoded regulator, Ler, plays a key role in relieving this repression at several major LEE promoters, including LEE2 to LEE5. To achieve appropriate intracellular concentrations of Ler in different environments, A/E pathogens have evolved a sophisticated regulatory network to control ler expression. For example, the LEE-encoded GrlA and GrlR proteins work as activator and antiactivator, respectively, of ler transcription. Thus, control of the transcriptional activities of the LEE1 (ler) promoter and the grlRA operon determines the rate of transcription of all of the LEE-encoded virulence factors. To date, only a single promoter has been identified for the grlRA operon. In this study, we showed that the non-LEE-encoded AraC-like regulatory protein RegA of C. rodentium directly stimulates transcription of the grlRA promoter by binding to an upstream region in the presence of bicarbonate ions. In addition, in vivo and in vitro transcription assays revealed a 70 promoter that is specifically responsible for transcription of grlA. Expression from this promoter was strongly repressed by H-NS and its paralog StpA but was activated by Ler. DNase I footprinting demonstrated that Ler binds to a region upstream of the grlA promoter, whereas H-NS interacts specifically with a region extending from the grlA core promoter into its coding sequence. Together, these findings provide new insights into the environmental regulation and differential expressions of the grlR and grlA genes of C. rodentium.Citrobacter rodentium causes transmissible colonic hyperplasia and diarrhea in mice (34). Like the human diarrheagenic pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC), C. rodentium induces attaching-and-effacing (A/E) lesions in the intestinal epithelium of its host (40, 49). All three of these enteric pathogens possess a pathogenicity island known as the locus for enterocyte effacement (LEE), which is responsible for the A/E phenotype (13,18,27,36,43). So far, all of the LEE-encoded virulence factors investigated in C. rodentium play roles in virulence equivalent to the roles played by those from EPEC and EHEC (14). Furthermore, the regulatory networks controlling transcription of the LEE are broadly similar in the three pathogens (37, 63). For these reasons, infection of mice with C. rodentium has been used as a convenient small animal model to investigate the molecular and cellular pathogenesis of EPEC and EHEC and the regulation of LEE expression by these organisms (14,40).The LEE comprises 41 open reading frames, most of which are clustered into five opero...

show abstract

Internal promoters of the rpoBC operon of Escherichia coli

Cited by 23 publications

References 15 publications

A missense mutation in the rpoC gene affects chromosomal replication control in Escherichia coli

A missense mutation in the rpoC gene affects chromosomal replication control in Escherichia coli

Relative activities of the transcriptional regulatory sites in the rplKAJLrpoBC gene cluster of Escherichia coli

Transcriptional Analysis of the grlRA Virulence Operon from Citrobacter rodentium

Contact Info

Product

Resources

About