Differential decay of a polycistronic <i>Escherichia coli</i> transcript is initiated by RNaseE‐dependent endonucleolytic processing

Nilsson, Pia; Uhlin, Bernt Eric

doi:10.1111/j.1365-2958.1991.tb01928.x

Cited by 80 publications

(72 citation statements)

References 47 publications

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“…Methylationdependent transcriptional regulation has been described for the pap operon, where the gene encoding the transcriptional activator PapB is co-transcribed with the gene of the major pilin subunit PapA and genes encoding additional pilus subunits from a promoter upstream of papB. The amount of the major pilin subunit PapA is a critical parameter for pilus synthesis (Nilsson & Uhlin, 1991). The second specific regulator for the synthesis of the Pap pilus is PapI.…”

Section: Discussionmentioning

confidence: 99%

The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K− : H6) is related to Pap pili but exhibits a truncated regulatory region

et al. 2003

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Adhesins provide a major advantage for uropathogenic Escherichia coli in establishing urinary tract infections (UTIs). A novel gene cluster responsible for the expression of a filamentous adhesin of the pyelonephritogenic E. coli strain X2194 has been identified, molecularly cloned, and characterized. The ‘pix operon’ contains eight open reading frames which exhibit significant sequence homology to corresponding genes in the pap operon encoding P pili, the prevalent E. coli adhesins in non-obstructive acute pyelonephritis in humans. Although a pixB gene corresponding to the PapB regulator was identified, a papI homologue could not be found in the pix operon. Instead, a fragment of the R6 gene of the highly uropathogenic E. coli strain CFT073 was identified upstream of pixB. The R6 gene is located in a pathogenicity island containing several pilus-encoding sequences and shows homology to a transposase of Chelatobacter heintzii. In a pixA–lacZ fusion system it was demonstrated that the expression of Pix pili is regulated at the transcriptional level by the R6 gene sequence. A significantly reduced transcription was observed by deleting this fragment and by lowering the growth temperature from 37 to 26 °C. In contrast to other filamentous adhesin systems, Pix pili are mainly expressed in the steady state growth phase and were not repressed by the addition of glucose.

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Section: Discussionmentioning

confidence: 99%

The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K− : H6) is related to Pap pili but exhibits a truncated regulatory region

et al. 2003

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“…Temperature is known to regulate translation by affecting mRNA conformation (2,18) or the translational machinery itself (reviewed in reference 22). The matA sequence contains four copies of putative RNase E target sequences (37), which might become accessible upon temperature-induced conformational change. Temperature may also affect the stability of the MatB protein.…”

Section: Discussionmentioning

confidence: 99%

matB , a Common Fimbrillin Gene of Escherichia coli , Expressed in a Genetically Conserved, Virulent Clonal Group

Pouttu¹,

Westerlund-Wikström²,

Lång³

et al. 2001

J Bacteriol

128

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A novel fimbrial type in Escherichia coli was identified and characterized. The expression of the fimbria was associated with the O18acK1H7 clonal group of E. coli, which cause newborn meningitis and septicemia when grown at low temperature; hence, it was named the Mat (meningitis associated and temperature regulated) fimbria. The fimbriae were purified from a fimA::cat sfaA::Gm fliC::St derivative of the O18K1H7 isolate E. coli IHE 3034. The purified Mat fimbrillin had an apparent molecular mass of 18 kDa and did not serologically cross-react with the type 1 or S fimbria of the same strain. The matB gene encoding the major fimbrillin was cloned from the genomic DNA of the fimA::cat sfaA::Gm fliC::St derivative of IHE 3034. The predicted MatB sequence was of 195 amino acids, contained a signal sequence of 22 residues, and did not show significant homology to any of the previously characterized fimbrial proteins. The DNA sequence of matB was 97.8% identical to a region from nucleotides 17882 to 18469 in the 6-to 8-min region of the E. coli K-12 chromosome, reported to encode a hypothetical protein. The 7-kb DNA fragment containing matB of IHE 3034 was found by restriction mapping and partial DNA sequencing to be highly similar to the corresponding region in the K-12 chromosome. Trans complementation of the matB::cat mutation in the IHE 3034 chromosome showed that matB in combination with matA or matC restored surface expression of the Mat fimbria. A total of 27 isolates representing K-12 strains and the major pathogroups of E. coli were analyzed for the presence of a matB homolog as well as for expression of the Mat fimbria. A conserved matB homolog was found in 25 isolates; however, expression of the Mat fimbriae was detected only in the O18acK1H7 isolates. Expression of the Mat fimbria was temperature regulated, with no or a very small amount of fimbriae or intracellular MatB fimbrillin being detected in cells cultivated at 37 o C. Reverse transcriptase PCR and complementation assays with mat genes controlled by the inducible trc promoter indicated that regulation of Mat fimbria expression involved both transcriptional and posttranscriptional events. Numerous proteinaceous adhesins have been detected inEscherichia coli (for recent reviews, see references 20 and 27). These adhesins occur in the form of fimbrial filaments or are nonfimbrial proteins of the outer membrane. The adhesins recognize different receptor molecules on the mammalian epithelia or extracellular matrices and function to enable colonization of E. coli at specific ecological niches. Many of the adhesins are associated with E. coli isolates from specific disease manifestations and contribute to the establishment of the infections. Examples of such disease-associated adhesins include the P fimbria of uropathogenic E. coli (UPEC) (55) and the various adhesin types detected in E. coli pathogroups causing diarrheal diseases (reviewed in references 13 and 36). Some adhesin genes, such as those encoding the mannosidebinding type 1 fimbriae (26) and th...

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“…This is one of the few clear cases of differential stability of coding segments of an RNA in B. subtilis. Another example is found in the dnaK operon (94), while examples abound in E. coli and (3,116,165,167). The processing site was mapped to an AU-rich sequence, 1 to 2 nt upstream of a weak hairpin (⌬G ϭ Ϫ9.1 kcal/mol).…”

Section: Stability Determinants Of Mrnasmentioning

confidence: 99%

RNA Processing and Degradation inBacillus subtilis

Condon

2003

Microbiol Mol Biol Rev

141

134

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This review focuses on the enzymes and pathways of RNA processing and degradation in Bacillus subtilis, and compares them to those of its gram-negative counterpart, Escherichia coli. A comparison of the genomes from the two organisms reveals that B. subtilis has a very different selection of RNases available for RNA maturation. Of 17 characterized ribonuclease activities thus far identified in E. coli and B. subtilis, only 6 are shared, 3 exoribonucleases and 3 endoribonucleases. Some enzymes essential for cell viability in E. coli, such as RNase E and oligoribonuclease, do not have homologs in B. subtilis, and of those enzymes in common, some combinations are essential in one organism but not in the other. The degradation pathways and transcript half-lives have been examined to various degrees for a dozen or so B. subtilis mRNAs. The determinants of mRNA stability have been characterized for a number of these and point to a fundamentally different process in the initiation of mRNA decay. While RNase E binds to the 5′ end and catalyzes the rate-limiting cleavage of the majority of E. coli RNAs by looping to internal sites, the equivalent nuclease in B. subtilis, although not yet identified, is predicted to scan or track from the 5′ end. RNase E can also access cleavage sites directly, albeit less efficiently, while the enzyme responsible for initiating the decay of B. subtilis mRNAs appears incapable of direct entry. Thus, unlike E. coli, RNAs possessing stable secondary structures or sites for protein or ribosome binding near the 5′ end can have very long half-lives even if the RNA is not protected by translation

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Differential decay of a polycistronic Escherichia coli transcript is initiated by RNaseE‐dependent endonucleolytic processing

Cited by 80 publications

References 47 publications

The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K− : H6) is related to Pap pili but exhibits a truncated regulatory region

The Pix pilus adhesin of the uropathogenic Escherichia coli strain X2194 (O2 : K− : H6) is related to Pap pili but exhibits a truncated regulatory region

matB , a Common Fimbrillin Gene of Escherichia coli , Expressed in a Genetically Conserved, Virulent Clonal Group

RNA Processing and Degradation inBacillus subtilis

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