ZNF384-Fusion Proteins Have High Affinity to EP300, Which Increases Their Transcriptional Activities

ZNF384 fusion (Z-fusion) genes are recently identified recurrent fusion genes of B-acute lymphoblastic leukemia (ALL) and cause differentiation block of B-cells; however, its molecular mechanisms have yet to be clarified. Common structural character of Z-fusion proteins is that fusion partners are fused to the N-terminal end of full-length ZNF384 (Figure 1A), suggesting that protein-fusions confer specific transcriptional targets on ZNF384. We searched Z-fusion-specific transcriptional targets that could cause differentiation block of B-cells by analyzing the data of gene expression profile of 54 primary B-ALL samples containing 9 Z-fusion positive ALL. We selected ID2 and SALL4 as potential targets. Both genes were expressed markedly higher in Z-fusion-positive ALL. ID2 acts as an inhibitor of E2A, B cell differentiation regulator, and SALL4 plays essential roles in maintaining pluripotency of embryonic stem cells. In the luciferase assays, EP300-ZNF384 (E-Z) and SYNRG-ZNF384 (S-Z) showed stronger transcriptional activities on the promoters of these genes than wild-type ZNF384 (Wild-Z). The introduction of E-Z or S-Z into 293T cells and THP-1 cells induced mRNA expression of these genes more strongly than that of Wild-Z (Figure 1B). We identified Z-fusion binding sites in the promoters of these genes. DNA binding abilities of Z-fusions to these sites were not stronger than that of Wild-Z in electro mobility shift assay. GST-pull down assay showed that E-Z associated with EP3...
Source: Blood - Category: Hematology Authors: Tags: 618. Acute Lymphoblastic Leukemia: Biology, Cytogenetics, and Molecular Markers in Diagnosis and Prognosis: Poster I Source Type: research