PAX5/TEL acts as a transcriptional repressor causing down-modulation of CD19, enhances migration to CXCL12, and confers survival advantage in pre-BI cells.

PAX5 is a transcription factor essential for B-cell development. Recently, it has been found as a frequent target of aberrancies in childhood acute lymphoblastic leukemia (ALL; 30% of B cell ALL cases), showing monoallelic loss, point mutations, or chromosomal translocations. The role of these aberrancies is still poorly understood. We previously cloned the PAX5/TEL fusion gene in a patient affected by B-cell precursor ALL with a t(9;12) translocation. This is the first report investigating the molecular and functional roles of PAX5/TEL protein in vitro from murine wild-type pre-BI cells. We showed that PAX5/TEL protein acts as an aberrant transcription factor with repressor function, recruiting mSin3A, down-regulating B220, CD19, BLNK, MB-1, FLT3, and mu heavy chain expression, thus suggesting a block on B-cell differentiation. In a PAX5-deficient context, the presence of PAX5/TEL did not replace PAX5 functions. PAX5/TEL protein enhances cell migration towards CXCL12, with the overexpression of CXCR4. Moreover, the presence of the fusion gene overcomes interleukin-7 withdrawal and interferes with transforming growth factor-beta1 pathway, inducing resistance and conferring cells an advantage in proliferation and survival. Thus, in vitro, the PAX5/TEL protein has a dominant effect on wild-type PAX5, interferes with the process of B-cell differentiation and migration, and induces resistance to apoptosis. Taken together, these phenomena likely represent key events in the process of B-cell transformation.

[1]  M. Busslinger,et al.  Pax5: the guardian of B cell identity and function , 2007, Nature Immunology.

[2]  J. Burger,et al.  The CXCR4 chemokine receptor in acute and chronic leukaemia: a marrow homing receptor and potential therapeutic target , 2007, British journal of haematology.

[3]  P. Brousset,et al.  A novel PAX5-ELN fusion protein identified in B-cell acute lymphoblastic leukemia acts as a dominant negative on wild-type PAX5. , 2007, Blood.

[4]  Christopher B. Miller,et al.  Genome-wide analysis of genetic alterations in acute lymphoblastic leukaemia , 2007, Nature.

[5]  A. Aloisi,et al.  TEL/ARG induces cytoskeletal abnormalities in 293T cells. , 2006, Cancer letters.

[6]  A. Biondi,et al.  Characterization of in vitro migratory properties of anti-CD19 chimeric receptor-redirected CIK cells for their potential use in B-ALL immunotherapy. , 2006, Experimental hematology.

[7]  S. Carotta,et al.  Repression of Flt3 by Pax5 is crucial for B-cell lineage commitment. , 2006, Genes & development.

[8]  T. Kipps,et al.  CXCR4: a key receptor in the crosstalk between tumor cells and their microenvironment. , 2006, Blood.

[9]  G. Blobe,et al.  Role of transforming growth factor-beta in hematologic malignancies. , 2006, Blood.

[10]  Marcel J. T. Reinders,et al.  Ig Gene Rearrangement Steps Are Initiated in Early Human Precursor B Cell Subsets and Correlate with Specific Transcription Factor Expression1 , 2005, The Journal of Immunology.

[11]  A. Rolink,et al.  A B220+ CD117+ CD19± hematopoietic progenitor with potent lymphoid and myeloid developmental potential , 2005, European journal of immunology.

[12]  S. Bohlander.  ETV6: a versatile player in leukemogenesis. , 2005, Seminars in cancer biology.

[13]  S. Orkin,et al.  Tel/Etv6 is an essential and selective regulator of adult hematopoietic stem cell survival. , 2004, Genes & development.

[14]  C. Garvie,et al.  Requirements for selective recruitment of Ets proteins and activation of mb-1/Ig-alpha gene transcription by Pax-5 (BSAP). , 2003, Nucleic acids research.

[15]  M. König,et al.  PAX5/ETV6 fusion defines cytogenetic entity dic(9;12)(p13;p13) , 2003, Leukemia.

[16]  C. Cotta,et al.  Pax5 determines B- versus T-cell fate and does not block early myeloid-lineage development. , 2003, Blood.

[17]  M. Schebesta,et al.  Pax5 promotes B lymphopoiesis and blocks T cell development by repressing Notch1. , 2002, Immunity.

[18]  M. Schebesta,et al.  Control of pre-BCR signaling by Pax5-dependent activation of the BLNK gene. , 2002, Immunity.

[19]  C. Schaniel,et al.  Stability and plasticity of wild‐type and Pax5‐deficient precursor B cells , 2002, Immunological reviews.

[20]  M. Busslinger,et al.  Reversion of B Cell Commitment upon Loss of Pax5 Expression , 2002, Science.

[21]  C. Schaniel,et al.  In vitro and in vivo plasticity of Pax5-deficient pre-B I cells. , 2002, Immunology letters.

[22]  C. Schaniel,et al.  Plasticity of Pax-5–/– Pre-B I Cells , 2002, Cells Tissues Organs.

[23]  C. Schaniel,et al.  Extensive in vivo self-renewal, long-term reconstitution capacity, and hematopoietic multipotency of Pax5-deficient precursor B-cell clones. , 2002, Blood.

[24]  Thomas D. Schmittgen,et al.  Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. , 2001, Methods.

[25]  S. Hiebert,et al.  TEL contacts multiple co-repressors and specifically associates with histone deacetylase-3 , 2001, Oncogene.

[26]  L. Kearney,et al.  The paired box domain gene PAX5 is fused to ETV6/TEL in an acute lymphoblastic leukemia case. , 2001, Cancer research.

[27]  A. Montpetit,et al.  Comparative analysis of the ETV6 gene in vertebrate genomes from pufferfish to human , 2001, Oncogene.

[28]  M. Busslinger,et al.  Pax5/BSAP maintains the identity of B cells in late B lymphopoiesis. , 2001, Immunity.

[29]  M. Greaves,et al.  Recruitment of the nuclear receptor corepressor N-CoR by the TEL moiety of the childhood leukemia-associated TEL-AML1 oncoprotein. , 2000, Blood.

[30]  C. Arrowsmith,et al.  DNA Binding Specificity Studies of Four ETS Proteins Support an Indirect Read-out Mechanism of Protein-DNA Recognition* 210 , 2000, The Journal of Biological Chemistry.

[31]  G. Nucifora,et al.  The leukemia-associated gene TEL encodes a transcription repressor which associates with SMRT and mSin3A. , 1999, Biochemical and biophysical research communications.

[32]  O. Bernard,et al.  TEL Is a Sequence-specific Transcriptional Repressor* , 1999, The Journal of Biological Chemistry.

[33]  Stephen L. Nutt,et al.  Commitment to the B-lymphoid lineage depends on the transcription factor Pax5 , 1999, Nature.

[34]  A. Rolink,et al.  B-cell development: a comparison between mouse and man. , 1998, Immunology today.

[35]  Y Fujiwara,et al.  The TEL/ETV6 gene is required specifically for hematopoiesis in the bone marrow. , 1998, Genes & development.

[36]  R. Berger,et al.  Analysis of TEL proteins in human leukemias , 1998, Oncogene.

[37]  A. M. Morrison,et al.  Identification of BSAP (Pax‐5) target genes in early B‐cell development by loss‐ and gain‐of‐function experiments , 1998, The EMBO journal.

[38]  A. M. Morrison,et al.  Loss- and gain-of-function mutations reveal an important role of BSAP (Pax-5) at the start and end of B cell differentiation. , 1998, Seminars in immunology.

[39]  F. Melchers,et al.  Murine B lymphopoiesis: towards a unified model. , 1998, Immunology today.

[40]  Jennings Cd,et al.  Recent Advances in Flow Cytometry: Application to the Diagnosis of Hematologic Malignancy , 1997 .

[41]  T. Golub,et al.  Yolk sac angiogenic defect and intra‐embryonic apoptosis in mice lacking the Ets‐related factor TEL , 1997, The EMBO journal.

[42]  J. Hoxie,et al.  The chemokine SDF‐1, stromal cell‐derived factor 1, attracts early stage B cell precursors via the chemokine receptor CXCR4 , 1997, European journal of immunology.

[43]  R. Berger,et al.  The TEL gene products: nuclear phosphoproteins with DNA binding properties , 1997, Oncogene.

[44]  D. Campana,et al.  Human B-cell progenitors and bone marrow microenvironment. , 1996, Human cell.

[45]  M. Busslinger,et al.  Deregulation of PAX-5 by translocation of the Emu enhancer of the IgH locus adjacent to two alternative PAX-5 promoters in a diffuse large-cell lymphoma. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[46]  M. Busslinger,et al.  DNA-binding and transactivation properties of Pax-6: three amino acids in the paired domain are responsible for the different sequence recognition of Pax-6 and BSAP (Pax-5) , 1995, Molecular and cellular biology.

[47]  M. Busslinger,et al.  The promoter of the CD19 gene is a target for the B-cell-specific transcription factor BSAP , 1992, Molecular and cellular biology.

[48]  Stephen L. Nutt,et al.  Commitment to the B-lymphoid lineage depends on the transcription factor Pax5 , 1999, Nature.

[49]  K. Foon,et al.  Recent advances in flow cytometry: application to the diagnosis of hematologic malignancy. , 1997, Blood.

[50]  R. Dalla‐Favera,et al.  The t(9;14)(p13;q32) chromosomal translocation associated with lymphoplasmacytoid lymphoma involves the PAX-5 gene. , 1996, Blood.

[51]  R. Scheuermann,et al.  CD19 antigen in leukemia and lymphoma diagnosis and immunotherapy. , 1995, Leukemia & lymphoma.

[52]  A. Rolink,et al.  B-lymphocyte lineage-committed, IL-7 and stroma cell-reactive progenitors and precursors, and their differentiation to B cells. , 1992, Advances in experimental medicine and biology.