Module 4: Understanding KO designs Mark Thomas Wellcome Trust Sanger Institute
Aims Understand design criteria and selection of critical exons View designs using genome browsers Assess the effect of a particular design on gene transcripts Search for design/allele information using BioMart
Design criteria One design, three alleles i)KO-first tagged allele ii)Wild-type conditional allele iii)Null-allele
Design criteria Tagged allele – requires insertion of reporter cassette, ideally located 5’ Wild-type conditional allele – requires native splicing to be maintained Null-allele – requires a critical exon that induces a frameshift Other considerations; - alternative splicing (ie. nAGxxnAG, exon skipping) - repeat elements - conserved elements - targeting efficiency (ie. Insertion size) - domain structure - translation reinitiation
Design criteria
Viewing designs Links to genome browsers Export for csv files
Viewing designs Design x
Viewing designs Conservation Repeats Design Gene Models mRNA transcripts
Viewing designs Conservation Repeats Design mRNA transcripts Gene Models U-oligos D-oligos
Viewing designs ConservationRepeats Design mRNA transcripts Gene Models
Assessing CE selection Transcript and Protein identifier links
Assessing CE selection Exons link
Assessing CE selection Exon sizes (bp) Intron/Exon phases U-oligos (intron 2) D-oligos
Assessing CE selection Coding Exons Protein Summary
KO: transcripts in VEGA
Fahd2a KO:Fahd2a Critical Exon
KO: transcripts in VEGA Fahd2a KO:Fahd2a Exon 3 - frameshifted
KO: transcripts in VEGA Fahd2a KO:Fahd2a Exon 3 Exon 3 – Alt. frame Exon 1
Custom design tool
Artificial intron designs AG|G or AG|A Knockout-first wt conditional Null allele
Artificial intron designs Exon 1 Exon 1b 1a Targeted allele
Using BioMart to search Simple searches using knockoutmouse.org More complex searches using biomart.org
Simple searches Simple searches using knockoutmouse.org Possible to browse by products, phenotype, location and name
Simple searches Simple searches using knockoutmouse.org
Simple searches Results page displays data from multiple resources
Simple searches Results page displays data from multiple resources
BioMart searches BioMart allows users to query databases using a standard interface.
BioMart searches GWAS Central - searching for interesting gene targets gwascentral.org Step 1. Use filters to restrict search parameters
BioMart searches Select attributes for results output
BioMart searches Apply additional filters to further restrict results
BioMart searches Results from GWAScentral knockoutmouse.org
BioMart searches knockoutmouse.org Vectors, ES cells and mice available
BioMart searches BioMart builds queries using a series of dropdown menus, identifying; Database selection Filters – defines search terms Attributes - selects results to be returned
BioMart searches Search results are returned in a table, containing links to data sources
BioMart searches Different databases/datasets can be linked in BioMart, allowing results to be combined. IKMC dataset Europhenome dataset
Resources Ensembl – VEGA – vega.sanger.ac.ukvega.sanger.ac.uk UCSC – genome.ucsc.edugenome.ucsc.edu MGI – IKMC portal – Europhenome – GWAScentral – BioMart –
Genbank Genbank files can be downloaded for every vector in IKMC
Genbank
Design criteria Max 3.5kb
Translation Re-initiation - critical exons should be as 5’ as possible Unless, the resulting KO translation is less than 35aa, as under these conditions translation may be reinitiated, producing an N-terminally truncated protein. Bcam
Translation Re-initiation ATGGAACCCCCTGACGCCCGCGCAGGGCTGCTGTGGCTCACCT TCCTGCTGTCGGGCTACTCAG GTTGATGGTACTGGGGCTCGACACCGTCTGGCTTCTGTGGAACCACAGGGCTCAGAGTTC CTGGGCACAGTCCACTCTCTGGGCCGCGTACCCCCATACGAGGTAGACTCTCGTGGGCGC CTGGTGATAGCAAAGGTCCAGGTGGGCGATGGACGGGACTACGTGTGCGTAGTGAAGGCT GGGGCAGCGGGTACCTCAGAGGCCACCTCAAGTGTCCGTGTGTTTG 1 MEPPDARAGL LWLTFLLSGY SG*WYWGSTP SGFCGTTGLR VPGHSPLSGP 51 RTPIRGRLSW APGDSKGPGG RWTGLRVRSE GWGSGYLRGH LKCPCV Translation