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Chimeric oncoprotein E2a-Pbx1 induces apoptosis of hematopoietic cells by a p53-independent mechanism that is suppressed by Bcl-2.
- Source :
-
Oncogene . 6/19/97, Vol. 14 Issue 24, p2917. 10p. - Publication Year :
- 1997
-
Abstract
- The chimeric oncoprotein E2a-Pbx1 results from fusion of the E2A and PBX1 genes following t(1;19) chromosomal translocations in B cell precursor acute leukemias. Experimentally B cell progenitors do not tolerate constitutive expression of E2a-Pbx1 which contrasts with transformation of several other cell types following its stable expression both in vitro and in vivo. To further investigate the effects of E2a-Pbx1 on the B cell progenitors, we conditionally expressed E2a-Pbx1 under control of a metal response element in hematopoietic precursor cell lines in vitro. Inducible expression of E2a-Pbx1 resulted in cell death with the morphologic and molecular features of apoptosis. A structure-function analysis demonstrated that induction of apoptosis was not a dominant-negative effect of the E2a moiety but, rather, required the DNA-binding homeodomain of Pbx1. E2a-Pbx1-induced apoptosis proceeded through a BCL2-responsive checkpoint eventuating in PARP inactivation but did require p53. Constitutive expression of E2a-Pbx1 did not induce apoptosis or continued cycling of Rat-1 fibroblasts in low serum conditions. These studies demonstrate that E2a-Pbx1 initiates programmed cell death of hematopoietic precursers by a mechanism that requires its chimeric transcriptional properties, but, unlike other nuclear oncoproteins, is independent of p53. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09509232
- Volume :
- 14
- Issue :
- 24
- Database :
- Academic Search Index
- Journal :
- Oncogene
- Publication Type :
- Academic Journal
- Accession number :
- 8917786
- Full Text :
- https://doi.org/10.1038/sj.onc.1201249