TY - JOUR A1 - Zheng, Xiaomin A1 - Oancea, Claudia A1 - Henschler, Reinhard A1 - Moore, Malcolm A. S. A1 - Ruthardt, Martin T1 - Reciprocal t(9;22) ABL/BCR fusion proteins: leukemogenic potential and effects on B cell commitment T2 - PLoS One N2 - Background: t(9;22) is a balanced translocation, and the chromosome 22 breakpoints (Philadelphia chromosome – Ph+) determine formation of different fusion genes that are associated with either Ph+ acute lymphatic leukemia (Ph+ ALL) or chronic myeloid leukemia (CML). The "minor" breakpoint in Ph+ ALL encodes p185BCR/ABL from der22 and p96ABL/BCR from der9. The "major" breakpoint in CML encodes p210BCR/ABL and p40ABL/BCR. Herein, we investigated the leukemogenic potential of the der9-associated p96ABL/BCR and p40ABL/BCR fusion proteins and their roles in the lineage commitment of hematopoietic stem cells in comparison to BCR/ABL. Methodology: All t(9;22) derived proteins were retrovirally expressed in murine hematopoietic stem cells (SL cells) and human umbilical cord blood cells (UCBC). Stem cell potential was determined by replating efficiency, colony forming - spleen and competitive repopulating assays. The leukemic potential of the ABL/BCR fusion proteins was assessed by in a transduction/transplantation model. Effects on the lineage commitment and differentiation were investigated by culturing the cells under conditions driving either myeloid or lymphoid commitment. Expression of key factors of the B-cell differentiation and components of the preB-cell receptor were determined by qRT-PCR. Principal Findings: Both p96ABL/BCR and p40ABL/BCR increased proliferation of early progenitors and the short term stem cell capacity of SL-cells and exhibited own leukemogenic potential. Interestingly, BCR/ABL gave origin exclusively to a myeloid phenotype independently from the culture conditions whereas p96ABL/BCR and to a minor extent p40ABL/BCR forced the B-cell commitment of SL-cells and UCBC. Conclusions/Significance: Our here presented data establish the reciprocal ABL/BCR fusion proteins as second oncogenes encoded by the t(9;22) in addition to BCR/ABL and suggest that ABL/BCR contribute to the determination of the leukemic phenotype through their influence on the lineage commitment. Y1 - 2009 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/22625 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30-114706 SN - 1932-6203 N1 - Copyright: © 2009 Zheng et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. VL - 4 IS - (10): e7661 ER -