2000 Fiscal Year Final Research Report Summary
Biologic characterization of leukemia-associated transcription factor AML1 (PEBP2αB) in hematopoiesis
| Project/Area Number |
11138251
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (A)
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| Allocation Type | Single-year Grants |
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| Research Institution | Kyoto Prefectural University of Medicine |
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Principal Investigator |
OKUDA Tsukasa Kyoto Prefectural University of Medicine, Department of Hygiene, Assistant Professor, 医学部, 講師 (30291587)
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| Project Period (FY) |
1999
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| Keywords | AML1 / PEBP2 / leukemia / hematopoiesis / transcription / embryonic stem (ES) cell / oncogene / gene targeting |
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| Research Abstract |
AML1 (PEBP2αB) is one of the most frequently mutated genes associated with human acute leukemia, and it encodes the DNA-binding subunit of the heterodimering transcriptional factor complex, core binding factor : CBF (or polyoma enhancer binding protein 2 : PEBP2). Disruption of either AML1 or its dimerizing partner, CBFβ (PEBP2β), results in the embryonic-lethality secondary to a complete block in fetal liver hematopoiesis, indicating an essential role of this transcription complex in the development of definitive hematopoiesis. The hematopoietic phenotype that results from the loss of AML1 could be replicated in vitro using a two-step culture system of murine embryonic stem (ES) cells. Using this experimental system, we demonstrated that this hematopoietic defect could be rescued by expressing the PEBP2αB1 (AML1b) isoform under the endogenous AML1-regulatory sequences through a knock-in (targeted-insertion) approach. Moreover, we found that these rescued AML1-/-ES cells could contribute to lympho-hematopoiesis within the context of chimeric animals. These results provide compelling evidence that the AML1 knockout phenotype is due solely to the lack of this gene, and that the PEBP2αB1 (AML1b) isoform is biologically active. Interestingly, hematopoietic rescue was not observed when AML1b was expressed under the control of a heterologous promoter, suggesting that the transcriptional control of AML1 is important for its biological activity. Using this assay, we also demonstrated that the transactivation domain of AML1b is required for its biological activity, whereas the conserved VWRPY-motif at the carboxyl terminus is not. The ES cell experimental system developed through the present study should serve as a unique tool to further define the biological properties of AML1 in normal and leukemic hematopoiesis.
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Research Products
(8 results)
