Tracing the pre-B to immature B cell transition in human leukemia cells reveals a coordinated sequence of primary and secondary IGK gene rearrangement, IGK deletion, and IGL gene rearrangement

J Immunol. 2005 Jan 1;174(1):367-75. doi: 10.4049/jimmunol.174.1.367.


The BCR-ABL1 kinase expressed in acute lymphoblastic leukemia (ALL) drives malignant transformation of pre-B cells and prevents further development. We studied whether inhibition of BCR-ABL1 kinase activity using STI571 can relieve this differentiation block. STI571 treatment of leukemia patients induced expression of the Ig L chain-associated transcription factors IRF4 and SPIB, up-regulation of RAG1 and RAG2, Ckappa and Clambda germline transcription, and rearrangement of Ig kappa L chain (IGK) and Ig lambda L chain (IGL) genes. However, STI571-treated pre-B ALL cells expressed lambda L, but almost no kappa L chains. This could be explained by STI571-induced rearrangement of the kappa-deleting element (KDE), which can delete productively rearranged Vkappa-Jkappa joints. Amplifying double-strand breaks at recombination signal sequences within the IGK, KDE, and IGL loci revealed a coordinated sequence of rearrangement events induced by STI571: recombination of IGK gene segments was already initiated within 1 h after STI571 treatment, followed by KDE-mediated deletion of Vkappa-Jkappa joints 6 h later and, ultimately, IGL gene rearrangement after 12 h. Consistently, up-regulation of Ckappa and Clambda germline transcripts, indicating opening of IGK and IGL loci, was detected after 1 and 6 h for IGK and IGL, respectively. Continued activity of the recombination machinery induced secondary IGK gene rearrangements, which shifted preferential usage of upstream located Jkappa- to downstream Jkappa-gene segments. Thus, inhibition of BCR-ABL1 in pre-B ALL cells 1) recapitulates early B cell development, 2) directly shows that IGK, KDE, and IGL genes are rearranged in sequential order, and 3) provides a model for Ig L chain gene regulation in the human.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • B-Lymphocytes / drug effects*
  • B-Lymphocytes / metabolism
  • Benzamides
  • DNA Primers
  • DNA-Binding Proteins / drug effects
  • DNA-Binding Proteins / metabolism
  • Flow Cytometry
  • Fusion Proteins, bcr-abl
  • Gene Expression Regulation, Neoplastic
  • Gene Rearrangement, B-Lymphocyte, Light Chain / drug effects*
  • Gene Rearrangement, B-Lymphocyte, Light Chain / genetics
  • Guanine Nucleotide Exchange Factors / drug effects
  • Guanine Nucleotide Exchange Factors / metabolism
  • Homeodomain Proteins / drug effects
  • Homeodomain Proteins / metabolism
  • Humans
  • Imatinib Mesylate
  • Immunoglobulins / genetics
  • Nuclear Proteins
  • Piperazines / therapeutic use
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / drug therapy
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / genetics*
  • Protein Kinase Inhibitors / therapeutic use*
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Pyrimidines / therapeutic use
  • Reverse Transcriptase Polymerase Chain Reaction
  • Stem Cells / drug effects*
  • Stem Cells / metabolism
  • Transcription Factors / drug effects
  • Transcription Factors / metabolism


  • Benzamides
  • DEF6 protein, human
  • DNA Primers
  • DNA-Binding Proteins
  • Guanine Nucleotide Exchange Factors
  • Homeodomain Proteins
  • IgK
  • Immunoglobulins
  • Nuclear Proteins
  • Piperazines
  • Protein Kinase Inhibitors
  • Pyrimidines
  • RAG2 protein, human
  • Transcription Factors
  • V(D)J recombination activating protein 2
  • RAG-1 protein
  • SPIB protein, human
  • Imatinib Mesylate
  • Protein-Tyrosine Kinases
  • Fusion Proteins, bcr-abl