Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs
<i>Escherichia coli</i> C is a strong biofilm producer in comparison to <i>E. coli</i> K-12 laboratory strains due to higher expression of the <i>pgaABCD</i> operon encoding the enzymes for the biosynthesis of the extracellular polysaccharide poly-β-1,6-<i>N...
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MDPI AG
2021-05-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/9/5/1010 |
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| author | Thomas Carzaniga Federica A. Falchi Francesca Forti Davide Antoniani Paolo Landini Federica Briani |
| author_facet | Thomas Carzaniga Federica A. Falchi Francesca Forti Davide Antoniani Paolo Landini Federica Briani |
| author_sort | Thomas Carzaniga |
| collection | DOAJ |
| description | <i>Escherichia coli</i> C is a strong biofilm producer in comparison to <i>E. coli</i> K-12 laboratory strains due to higher expression of the <i>pgaABCD</i> operon encoding the enzymes for the biosynthesis of the extracellular polysaccharide poly-β-1,6-<i>N</i>-acetylglucosamine (PNAG). The <i>pgaABCD</i> operon is negatively regulated at the post-transcriptional level by two factors, namely CsrA, a conserved RNA-binding protein controlling multiple pathways, and the RNA exonuclease polynucleotide phosphorylase (PNPase). In this work, we investigated the molecular bases of different PNAG production in C-1a and MG1655 strains taken as representative of <i>E. coli</i> C and K-12 strains, respectively. We found that <i>pgaABCD</i> operon expression is significantly lower in MG1655 than in C-1a; consistently, CsrA protein levels were much higher in MG1655. In contrast, we show that the negative effect exerted by PNPase on <i>pgaABCD</i> expression is much stronger in C-1a than in MG1655. The amount of CsrA and of the small RNAs CsrB, CsrC, and McaS sRNAs regulating CsrA activity is dramatically different in the two strains, whereas PNPase level is similar. Finally, the compensatory regulation acting between CsrB and CsrC in MG1655 does not occur in <i>E. coli</i> C. Our results suggest that PNPase preserves CsrA-dependent regulation by indirectly modulating <i>csrA</i> expression. |
| first_indexed | 2024-03-10T11:37:26Z |
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| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T11:37:26Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-4f0887cf4f1b4383a112e2b5614a5a772023-11-21T18:44:19ZengMDPI AGMicroorganisms2076-26072021-05-0195101010.3390/microorganisms9051010Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAsThomas Carzaniga0Federica A. Falchi1Francesca Forti2Davide Antoniani3Paolo Landini4Federica Briani5Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, ItalyDipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy<i>Escherichia coli</i> C is a strong biofilm producer in comparison to <i>E. coli</i> K-12 laboratory strains due to higher expression of the <i>pgaABCD</i> operon encoding the enzymes for the biosynthesis of the extracellular polysaccharide poly-β-1,6-<i>N</i>-acetylglucosamine (PNAG). The <i>pgaABCD</i> operon is negatively regulated at the post-transcriptional level by two factors, namely CsrA, a conserved RNA-binding protein controlling multiple pathways, and the RNA exonuclease polynucleotide phosphorylase (PNPase). In this work, we investigated the molecular bases of different PNAG production in C-1a and MG1655 strains taken as representative of <i>E. coli</i> C and K-12 strains, respectively. We found that <i>pgaABCD</i> operon expression is significantly lower in MG1655 than in C-1a; consistently, CsrA protein levels were much higher in MG1655. In contrast, we show that the negative effect exerted by PNPase on <i>pgaABCD</i> expression is much stronger in C-1a than in MG1655. The amount of CsrA and of the small RNAs CsrB, CsrC, and McaS sRNAs regulating CsrA activity is dramatically different in the two strains, whereas PNPase level is similar. Finally, the compensatory regulation acting between CsrB and CsrC in MG1655 does not occur in <i>E. coli</i> C. Our results suggest that PNPase preserves CsrA-dependent regulation by indirectly modulating <i>csrA</i> expression.https://www.mdpi.com/2076-2607/9/5/1010CsrAPNPase<i>pgaABCD</i> operonauto-aggregationbiofilmpoly-β-1,6-<i>N</i>-acetylglucosamine |
| spellingShingle | Thomas Carzaniga Federica A. Falchi Francesca Forti Davide Antoniani Paolo Landini Federica Briani Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs Microorganisms CsrA PNPase <i>pgaABCD</i> operon auto-aggregation biofilm poly-β-1,6-<i>N</i>-acetylglucosamine |
| title | Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs |
| title_full | Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs |
| title_fullStr | Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs |
| title_full_unstemmed | Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs |
| title_short | Different <i>csrA</i> Expression Levels in C versus K-12 <i>E</i>. <i>coli</i> Strains Affect Biofilm Formation and Impact the Regulatory Mechanism Presided by the CsrB and CsrC Small RNAs |
| title_sort | different i csra i expression levels in c versus k 12 i e i i coli i strains affect biofilm formation and impact the regulatory mechanism presided by the csrb and csrc small rnas |
| topic | CsrA PNPase <i>pgaABCD</i> operon auto-aggregation biofilm poly-β-1,6-<i>N</i>-acetylglucosamine |
| url | https://www.mdpi.com/2076-2607/9/5/1010 |
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