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SRX2515501: GSM2467975: IP7-treat; Legionella pneumophila str. Paris; RIP-Seq
1 ILLUMINA (Illumina HiSeq 2000) run: 123.2M spots, 6.3G bases, 2.3Gb downloads

Submitted by: NCBI (GEO)
Study: The Legionella pneumophila genome evolved to accommodate multiple regulatory mechanisms controlled by the CsrA-system
show Abstracthide Abstract
The RNA binding protein CsrA is the master regulator of the bi-phasic life cycle of Legionella pneumophila governing virulence expression in this intracellular pathogen. The goal of the study was to use deep sequencing of RNA enriched by co-immunoprecipitation with epitope tagged CsrA to identify CsrA-associated transcripts at the genome level. We found 478 mRNAs or non-coding RNAs to be targets of CsrA. Among those major regulators including FleQ, the regulator of flagella expression, LqsR, the regulator of quorum sensing and RpoS implicated in stress response were identified. The expression of over 40 type IV secreted effector proteins important for intracellular survival and virulence are under the control of CsrA. Combined with transcriptomics, whole shotgun proteomics of a wild type and a CsrA mutant strain and functional analyses of several CsrA-targeted RNAs we identified the first riboswitch in L. pneumophila, a thiamine pyrophosphate riboswitch, and discovered a new mode of regulation by CsrA that allows L. pneumophila to regulate the pentose phosphate pathway and the glycolysis combined or individually although they share genes in a single operon. Our results further underline the indispensable role of CsrA in the life cycle of L. pneumophila and provide new insights into its regulatory roles and mechanisms. Overall design: For each RIP-seq experiment, epitope-tagged CsrA protein and CsrA without Flag-Tag as negative control was used in parallel to perform the library construction. In total, 5 independent libraries (biological replicates) were executed for both, called IP1, IP2, IP7, IP8 and IP9.
Sample: IP7-treat
SAMN06270336 • SRS1938710 • All experiments • All runs
Library:
Instrument: Illumina HiSeq 2000
Strategy: RIP-Seq
Source: TRANSCRIPTOMIC
Selection: other
Layout: SINGLE
Construction protocol: Cell pellets were resuspended in lysis buffer (50mM HEPES-KOH pH7.5, 150mM NaCl, 1mM EDTA, 1% Triton X-100, 0.1% Na-deoxycholate, protease inhibitor), sonicated and total protein concentrations were adjusted to 1mg/ml. The total protein of both samples, CsrA+2xFlagTag and negative control, was cleared separately by BSA-blocked Dynabeads protein G (Invitrogen) and subsequently incubated with Dynabeads protein G coupled to Anti-Flag antibodies (Sigma) over night at 4°C on a rotating platform. Samples and negative control were washed twice with Lysis buffer containing 350mM NaCl and 5 times with wash buffer (10mM Tris-HCl pH 7.5, 250 mM NaCl, 0.5% NP-40, 0.5% Na-deoxycholate, 1mM EDTA). Subsequently beads were washed with TE buffer, resuspended in elution buffer (50mM Tris-HCl pH 8.0, 1mM EDTA, 1% SDS) and incubated at 65°C for 30 min. Crosslinking was reversed and DNA and protein were digested to get purified RNA. The RNA was metal-catalyzed heat fragmented to a size around 100-200nt using the RNA fragmentation kit and the RNA of both independent samples was purified and further processed according to the TruSeq stranded mRNA sample preparation guide of Illumina. The two parallel processed samples were ligated with adaptor 6 (positive CsrA+2xFlagTag library) and adaptor 12 (negative control, minus FlagTag), respectively, the quantity was determined using a Qubit 2.0 (Invitrogen) and the quality was checked using a Bioanalyzer. High quality libraries were sequenced using an Illumina HiSeq platform. This experiment was done in 5 replicates.
Experiment attributes:
GEO Accession: GSM2467975
Links:
Runs: 1 run, 123.2M spots, 6.3G bases, 2.3Gb
Run# of Spots# of BasesSizePublished
SRR5201554123,220,8606.3G2.3Gb2017-01-27

ID:
3643380

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