|Gene:||mcaS||Accession Numbers: G0-8899 (EcoCyc), b4426, ECK1336|
Synonyms: IS061, isrA
Superclasses: a regulatory RNA
McaS is a Hfq-binding small RNA that regulates the expression of curli by inhibiting translation and enhancing degradation of csgD mRNA. Conversely, it positively regulates flagellar motility and biofilm formation [Jorgensen12, Thomason12, De12]. McaS not only acts as a direct regulator of translation by base-pairing with the 5' UTRs of mRNAs, but also indirectly by binding and sequestering CsrA, a global post-transcriptional regulator. In addition to pgaABCD, other regulatory targets of CsrA, including dgcZ, ycdT and glgC, are thereby indicrectly regulated by McaS [Jorgensen13].
McaS has at least two GGA sequence elements that function as CsrA-binding sequences; McaS binds CsrA with an apparent Kd of 0.71 nM [Jorgensen13].
The half life of McaS is strongly reduced in the absence of Hfq. mcaS expression in rich medium is highest during the transition from log to stationary phase; in minimal medium with glycerol, expression is highest during logarithmic growth [Jorgensen12, Thomason12]. Overexpression of mcaS inhibits production of curli and lowers the expression of csgD [Jorgensen12]. Conversely, it positively regulates expression of flhD and pgaA, leading to increased motility and biofilm formation [Thomason12, De12, Jorgensen13].
McaS (IS061) was first identified as a potential small RNA of approximately 85-90 nt in length [Chen02a].
Using a network biology approach, both GlmZ and McaS (IsrA) were predicted to be involved in the DNA damage response. A glmZ mcaS double mutant is less sensitive to DNA damaging agents and has a lower basal mutation rate than wild type [Modi11].
|Map Position: [1,403,683 <- 1,403,775] (30.25 centisomes, 109°)||Length: 93 bp|
|Biological Process:||GO:0045947 - negative regulation of translational initiation
GO:0045948 - positive regulation of translational initiation [Thomason12]
GO:0051100 - negative regulation of binding [Jorgensen13]
GO:0070928 - regulation of mRNA stability, ncRNA-mediated [Jorgensen12]
|Molecular Function:||GO:0005515 - protein binding
GO:0048027 - mRNA 5'-UTR binding [Jorgensen12]
|MultiFun Terms:||information transfer → RNA related → antisense RNA|
|regulation → type of regulation → posttranscriptional → antisense RNA|
|regulation → type of regulation → posttranscriptional → inhibition / activation of enzymes|
|regulation → type of regulation → posttranscriptional → translation attenuation and efficiency|
Ingrid Keseler on Wed Jan 25, 2012:
Gene coordinates updated based on information in [Jorgensen12 ].
Suzanne Paley on Thu Oct 21, 2004:
Position updated based on U00096.2 release of genome
Chen02a: Chen S, Lesnik EA, Hall TA, Sampath R, Griffey RH, Ecker DJ, Blyn LB (2002). "A bioinformatics based approach to discover small RNA genes in the Escherichia coli genome." Biosystems 65(2-3);157-77. PMID: 12069726
Jorgensen12: Jorgensen MG, Nielsen JS, Boysen A, Franch T, Moller-Jensen J, Valentin-Hansen P (2012). "Small regulatory RNAs control the multi-cellular adhesive lifestyle of Escherichia coli." Mol Microbiol 84(1);36-50. PMID: 22250746
Modi11: Modi SR, Camacho DM, Kohanski MA, Walker GC, Collins JJ (2011). "Functional characterization of bacterial sRNAs using a network biology approach." Proc Natl Acad Sci U S A 108(37);15522-7. PMID: 21876160
Thomason12: Thomason MK, Fontaine F, De Lay N, Storz G (2012). "A small RNA that regulates motility and biofilm formation in response to changes in nutrient availability in Escherichia coli." Mol Microbiol 84(1);17-35. PMID: 22289118
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