Keio and ASKA collections

Dear internet,
Our lab is unable to distribute the Keio/ASKA strains to other institutions. We did not create them! If you want to use these fantastic E. coli resources for your research, here are two options:

  1. Preferred source: If you want a few strains or the full collection, you can submit a request to the National BioResource Project at SHIGEN where the strains were created. This page is also the most comprehensive information on these strains, including a list of strains in which genes were not successfully disrupted.

  2. To get a few individual strains, you may also be able to request them from the E. coli Genetic Stock Center (CGSC) at Yale.

The Keio collection consists of single-gene knockout strains in the K12 BW25113 strain background (an MG1655 derivative). They contain a KanR resistance cassette in place of the gene. One can easily remove this cassette to create an in-frame deletion of the gene using FLP recombinase expression from plasmid pCP20.

The ASKA collection is a set of ORFs cloned from E. coli K12 W3110 into the high copy number plasmid pCA24N. This plasmid has a modified pMB1 replication origin (same as pQE30 from Qiagen) and CamR marker. The cloned ORF is under control of the IPTG-inducible T5-lac promoter.

Our samples of these strain collections were transferred from 96-well microplates into 384-well microplates using a 96-well pin tool. Thus, the plates are interspersed with one another, with one plate in the upper-left register, the next plate in the upper right register, the third plate in the lower left register, and the final plate in the lower right register. This is the layout in the order listed on the plate label. The attached spreadsheets can be used to determine if a strain exists in the collection (be sure you search gene synonyms) and to find the well number for a desired strain to retrieve it.

Important! When retrieving a strain from the freezer and regrowing it:

  1. Streak out to a single colony on an LB agar plate with the correct antibiotic.
  2. Verify that the strain/plasmid is correct.
    • By comparing PCR product size or a known phenotype to BW25113 for Keio Strains
    • By sequencing the plasmid insert for ASKA strains. Sequencing primers SPL003 and SPL004 flank the ORF insertion site in the pCA24N.
  3. Create a stock of this verified isolate in a cryovial for further use by the lab.

Some known issues with our copy of the Keio collection

  • JW0578 ( entF) has some slight contamination from JW3684 ( trmE)
  • We were unable to revive JW5830 mntP ( yebN)
  • We were unable to revive JW5807 leuB
Topic attachments
I Attachment History Action Size Date Who Comment
Microsoft Excel Spreadsheetxls Platesheet__ASKA_96_384.xls r1 manage 368.5 K 2014-06-26 - 22:07 SeanLeonard Spreadsheet updated to include clone locations on 384 well plates
Microsoft Excel Spreadsheetxls keio.collectionsheet.xls r4 r3 r2 r1 manage 856.0 K 2014-05-30 - 10:56 JeffreyBarrick Keio collection microplate layout, including 96- and 384-well plate versions
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 Barrick Lab  >  ProtocolList  >  ReferenceKeioASKACollection

Contributors to this topic Edit topic JeffreyBarrick, SeanLeonard, CraigBarnhart, SimonDAlton
Topic revision: r15 - 2020-03-27 - 11:22:13 - Main.JeffreyBarrick
 
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