Extended Data Fig. 3: BAHCC1 potentiates acute leukemia growth in vivo, a function that relies on an evolutionarily conserved BAH domain (BAHCC1^BAH) as an H3K27me3/2-specific ‘reader’.

a, b, Bioluminescence imaging (a, two weeks post-transplantation) and Kaplan-Meier survival curve (b) of NSG mice xenografted with luciferase-labeled CUTLL1 cells post-transduction of empty vector or a BAHCC1-targeting shRNA. c, Averaged bioluminescence signals (collected from ventral view) of NSG mice xenografted with luciferase-labeled OCI-AML3 cells that harbor the CRISPR-Cas9-introduced disruption of BAHCC1^BAH (ΔBAH), relative to WT (n=5 mice). Data are presented as mean ± SD. d, Plot showing the in vivo growth of K562 cell subcutaneous xenografts, after BAHCC1 KD or mock treatment. Data of tumor volume was shown as mean ± SD for each group (n=8). e, Images of K562 subcutaneous xenografts excised from the indicated cohort at the end of experiments. f, Domain architecture of the Homo sapiens, Mus musculus, Xenopus tropicalis and Danio rerio BAHCC1 proteins, revealing a conserved BAH domain (BAHCC1^BAH). g, Alignment using the amino acid sequences of BAHCC1^BAH from different species. Conserved residues are highlighted in red. The secondary structure is drawn based on the BAHCC1:H3K27me3 co-crystal structure, with the H3K27me3-caging and other histone-binding residues designated by red stars and black dots, respectively. h-i, Peptide pulldown using GST-BAHCC1^BAH (h) or GST-ORC1^BAH (i) protein and biotinylated histone H3.1 or H4 peptide carrying the indicated methylation (bottom). Unmodi, un-modified. j-p, ITC fitting curves of BAHCC1^BAH with the indicated histone peptide. q, Summary of thermodynamic and curve fitting parameters for ITC assays using murine BAHCC1^BAH recombinant protein and histone peptide. NDB, no detectable binding. *, N value set manually. ^#, mean and SD values derived from two independent measurements. For all the other titrations, ITC parameters were determined by curve fitting of single titration. **, due to behavior of CBX7^CD and for a comparable measurement, ITC was performed at 25 °C instead of 7 °C for other measurements.