This CRISPR domain screen identified the second Tudor domain of SGF29 (SGF29_Tudor 2) (14), a histone H3K4me3 binding protein in the SAGA and ATAC histone modification complexes (23, 24), as the top essential Tudor domain in MLL-AF9 leukemia (Fig. 1B and data S3). This evidence concerns the gene SGF29 and leukemia.