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Lentiviral-mediated Knockdown During Ex Vivo Erythropoiesis of Human Hematopoietic Stem Cells
Published on: July 16, 2011
LSD1-mediated epigenetic modification is required for TAL1 function and hematopoiesis.
Xin Hu1, Xingguo Li, Kristell Valverde
1Departments of Biochemistry and Molecular Biology and Anatomy and Cell Biology, Genetics Institute, and Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32610, USA.
Summary
Histone demethylase LSD1 negatively regulates TAL1 transcription. Its dynamic regulation with HDAC1 during erythroid differentiation is crucial for initiating red blood cell development and preventing leukemia.
Area of Science:
- Hematopoiesis and Cancer Biology
- Epigenetics and Gene Regulation
Background:
- TAL1 is essential for blood cell development but can drive T cell leukemia when dysregulated.
- Mechanisms controlling TAL1 transcriptional activity during hematopoiesis are not fully understood.
Purpose of the Study:
- To investigate the role of histone demethylase complexes in regulating TAL1 transcriptional activity during hematopoiesis.
- To elucidate the dynamic changes in TAL1-associated complexes during erythroid differentiation.
Main Methods:
- Co-immunoprecipitation to identify TAL1-associated complexes.
- Reporter gene assays to assess TAL1 transcriptional activity.
- shRNA-mediated knockdown of LSD1 in murine erythroleukemia (MEL) cells.
- Chromatin immunoprecipitation to analyze histone modifications (H3K4 methylation).
Main Results:
- TAL1 forms complexes with LSD1, CoREST, HDAC1, and HDAC2 in leukemia cells.
- LSD1's enzymatic activity represses TAL1-driven transcription.
- TAL1-associated LSD1 and HDAC1 activities decrease during early erythroid differentiation.
- LSD1 is recruited to the p4.2 promoter in undifferentiated MEL cells but not in differentiated cells.
- LSD1 knockdown derepresses TAL1 target genes and increases H3K4 methylation at promoters.
Conclusions:
- Histone lysine demethylase LSD1 negatively regulates TAL1-mediated transcription.
- Dynamic regulation of the TAL1-associated LSD1/HDAC1 complex is critical for initiating erythroid differentiation.
- Dysregulation of this complex may contribute to the development of T cell leukemia.
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