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MGH-PGA Genomic Analysis of Stress and Inflammation: Pseudomonas aeruginosa Strain PA14 Non-Redundant Mutant Library Nicole T. Liberati, Dan G. Lee, Jacinto.

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Presentation on theme: "MGH-PGA Genomic Analysis of Stress and Inflammation: Pseudomonas aeruginosa Strain PA14 Non-Redundant Mutant Library Nicole T. Liberati, Dan G. Lee, Jacinto."— Presentation transcript:

1 MGH-PGA Genomic Analysis of Stress and Inflammation: Pseudomonas aeruginosa Strain PA14 Non-Redundant Mutant Library Nicole T. Liberati, Dan G. Lee, Jacinto M. Villanueva and Frederick M. Ausubel Department of Molecular Biology Massachusetts General Hospital

2 How Good is the Throughput for Screening for P. aeruginosa Virulence Factors? 32 Pathogenicity genes identified out of 8,000 mutants screened. Genome size is ~6.5 Mb: ~5500 non-essential genes. Computer simulation: Screen ~30,000 random insertions to reach 95% saturation. Construct non-redundant library by sequencing 30,000 transposon insertion sites. –Limited number of mutants to screen (~5500). –Learn which genes are NOT involved in a particular process.

3 1st PCR Reaction 2nd PCR Reaction PCR Cleanup and Sequencing 1 2 3 Arbitrary PCR to Amplify Sequence Adjacent to Transposon Insertion Transposon

4 PA14 Non-Redundant Library Protocol Plates with PA14 Transposon Mutants Cultures in 384 well plates Arbitrary PCR 1 96 well plates Arbitrary PCR 2 96 well plates Sequencing QBOT MySQL PA14 Database PA14 & PA01 Genomes Robot Biomek Robot Biomek 4. BLAST analysis 3. PHRED trimming 1. catalog 2. Record correspondences Biomek

5 Current Status of the Non-Redundant Library 45 x 384 (17,280) mutants generated Projected date of completion: 12/31/03 Insertions are reasonably random: 20 40 60 80 100 0 # insertions/10Kb Chromosomal Location 1,000,0002,000,0003,000,0004,000,0005,000,0006,000,000 TnphoA Mariner

6 Gm resistance Mariner Transposase Amp resistance pir-dependent ori Inserted into the PA14 genome: T7 Promoter** Tra genes pMAR 2xT7 lacZ T7 Promoter Mariner: pMFLGM.GB*- 2xT7 (pMAR 2XT7) 29 bp IR** 29 bp IR ** From Eric Rubin’s lab* From John Mekalanos’s lab

7 The PA14 Transposon Insertion Mutant Database (http://pga.mgh.harvard.edu/cgi-bin/pa14/mutants/retrieve.cgi) Authors: Daniel G. Lee, Nicole T. Liberati, Jonathan M. Urbach, Eric VanHelene, Jacinto M Villanueva,Tao Wei Frederick M. Ausubel

8 Database Request Page (http://pga.mgh.harvard.edu/cgi-bin/pa14/mutants/retrieve.cgi)

9 How Good is the Throughput for Screening for P. aeruginosa Virulence Factors? 32 Pathogenicity genes identified out of 8,000 mutants screened. Genome size is ~6.5 Mb: ~5500 non-essential genes. Screen ~30,000 random insertions to reach 95% saturation. Screen in several model hosts to identify all virulence factors. Screening for mutant phenotypes is rate limiting. Construct non-redundant library by sequencing 30,000 transposon insertion sites.

10 An arrayed collection of P. aeruginosa strains containing a known disruption in each non-essential open reading frame (ORF) in the genome Wild typeMutant #1Mutant #2 Non-Redundant Library Advantages : Limited number of mutants to screen (~5500). Learn which genes are NOT involved in a particular process.

11 Transposon: Kan r E. Coli P. aeruginosa Transposase Generation of Transposon Insertion Mutations Select for kanamycin-resistant P. aeruginosa

12 Non-redundant mutants from PA14 library A CB ABC Control Growth Condition (rich media) “red” probe Experimental Growth Condition (murine CF lung) “green” probe #1 #2 #3 Gene A oligos Gene B oligos Gene C oligos Microarray: 2 oligonucleotides Flanking each Insertion in the library “TraSH”* Methodology: Detection of the Absence of Transposon Mutant(s) in a Pool of Mutants *Transposon-Site Hybridization Sassetti, C. M., Boyd, D. H., and Rubin, E. J., (2001). PNAS 9812712-12717Badarinarayana, V., et al. (2001) Nature Biotechnology 19:1060-5

13 ~6.5 Mb ~5,500 non-essential genes ~5,225 non-redundant mutants 27,500 insertions 32,500 insertions Transposon Mutagenesis 5 fold excess Recovery/Sequencing failures Non-Redundant Library Size Choose most 5’ insertion in each ORF


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