Journal: Genes & Development
Article Title: A cryptic Tudor domain links BRWD2/PHIP to COMPASS-mediated histone H3K4 methylation
Figure Lengend Snippet: Characterization of the BRWD2/PHIP CryptoTudor domain. ( A ) Diagram depicting the recombinant BRWD2/PHIP CryptoTudor–bromodomain (BRWD2/PHIP–Crypt–bromo) construct used for binding studies. N-terminal 10X-Histidine (red box) and C-terminal 1XFlag (green box) tags were included for protein purification. ( B ) Coomassie stained SDS-PAGE gel of in vitro chromatin capture experiment using the BRWD2/PHIP–Crypt–bromo module. (Lane 1 ) Input MNase-digested chromatin. (Lane 2 ) Chromatin subjected to anti-Flag immunoprecipitation without BRWD2/PHIP–Crypt–bromo. (Lane 3 ) Chromatin incubated with recombinant BRWD2/PHIP–Crypt–bromo and subjected to anti-Flag immunoprecipitation. ( C ) Quantitative MS analysis of histones captured in B . Bars indicate the fraction of total histone represented by each modification state in the input (gray) or Flag immunoprecipitation material (red). (Un) Unmodified; (me1) monomethylated; (me2) dimethylated; (me3) trimethylated; (Ac) acetylated. ( D ) Coomassie-stained SDS-PAGE gel of histone peptide pull-downs performed with human ( top ) or Drosophila ( bottom ) Crypt–bromo constructs. Recombinant protein was incubated with streptavidin beads alone (SA-beads) or the biotinylated histone peptides indicated. Ten percent of input and 20% of each pull-down sample were loaded. ( Bottom ) Eluted proteins were subjected to dot blotting using streptavidin-HRP (SA-HRP). ( E ) ITC experiments with human BRWD2–Crypt–bromo titrated with H3 unmodified ( left ), H3K4me1 ( middle ), and H3K4me3 ( right ) peptides. ( F ) Coomassie-stained SDS-PAGE gel of pull-downs performed with human BRWD2/PHIP–Crypt–bromo and a panel of histone peptides. Ten percent of input and 20% of each pull-down sample were loaded. Streptavidin-HRP dot blot loading control is shown below the gel image. ( G ) Coomassie-stained SDS-PAGE gel of a panel of histone peptide pull-downs performed with human BRWD2–Crypt–bromo ( top ), the isolated CryptoTudor domain ( middle ), or the isolated tandem bromodomains ( bottom ). Ten percent of input and 20% of each pull-down sample were loaded. Dot blot loading control is shown below each gel image. ( H ) Coomassie-stained gels of histone peptide pull-downs performed with point mutations of the BRWD2 CryptoTudor domain. Dot blot loading controls are shown below the gels. ( I ). Positions of residues predicted to be involved in methyl-lysine binding are highlighted in red.
Article Snippet: As a loading control, 0.25 µL of the eluted proteins was spotted onto a nitrocellulose membrane and detected using streptavidin-HRP (Thermo Scientific, no. 21130).
Techniques: Recombinant, Construct, Binding Assay, Protein Purification, Staining, SDS Page, In Vitro, Immunoprecipitation, Incubation, Mass Spectrometry, Modification, Dot Blot, Isolation