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Updated: Jul 11, 2026
09:16
Investigation of the Transcriptional Role of a RUNX1 Intronic Silencer by CRISPR/Cas9 Ribonucleoprotein in Acute Myeloid Leukemia Cells
Published on: September 1, 2019
RUNX1/EVI1, which blocks myeloid differentiation, inhibits CCAAT-enhancer binding protein alpha function
Katsuya Tokita1, Kazuhiro Maki, Kinuko Mitani
1Department of Hematology, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi 321-0293, Japan.
Cancer Science
|September 27, 2007
Summary
The RUNX1/EVI1 fusion protein blocks myeloid cell differentiation by inhibiting CCAAT-enhancer binding protein alpha (C/EBPalpha). Restoring C/EBPalpha function rescues differentiation, suggesting C/EBPalpha inhibition drives leukemia.
Area of Science:
- Hematology
- Molecular Biology
- Oncology
Background:
- The RUNX1/EVI1 fusion protein, resulting from t(3;21), is implicated in leukemic transformation.
- This fusion protein is thought to induce leukemia by blocking the differentiation of malignant myeloid progenitors.
- A dominant-negative effect on wild-type RUNX1 is a proposed molecular mechanism.
Purpose of the Study:
- To investigate the molecular mechanisms underlying RUNX1/EVI1-mediated differentiation block.
- To determine how RUNX1/EVI1 affects the function of CCAAT-enhancer binding protein alpha (C/EBPalpha), a key regulator of granulocytic differentiation.
Main Methods:
- Introduction of RUNX1/EVI1 cDNA into LG-3 cells to study differentiation suppression.
- Reporter assays using the CEBPA promoter to assess RUNX1/EVI1's effect on C/EBPalpha activity.
- Gel-shift assays to evaluate RUNX1/EVI1's impact on C/EBPalpha DNA-binding activity.
Main Results:
- RUNX1/EVI1 suppressed myeloid differentiation in LG-3 cells.
- RUNX1/EVI1 associated with C/EBPalpha and exhibited a dominant-negative effect on C/EBPalpha-mediated transcription.
- RUNX1/EVI1 downregulated the DNA-binding activity of C/EBPalpha.
- Coexpression of C/EBPalpha restored differentiation in RUNX1/EVI1-expressing cells.
Conclusions:
- RUNX1/EVI1 inhibits myeloid differentiation by interfering with C/EBPalpha function.
- Mechanisms include dominant-negative repression of C/EBPalpha activity, potentially via histone deacetylase recruitment and disrupted DNA binding.
- Inhibition of C/EBPalpha is likely causally linked to the leukemogenic potential of RUNX1/EVI1.
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