Siegfried Janz

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Chromosomal translocations juxtaposing the MYC protooncogene with regulatory sequences of immunoglobulin (Ig) H chain or kappa (Ig kappa) or lambda (Ig lambda) L chain genes and effecting deregulated expression of MYC are the hallmarks of human Burkitt lymphoma (BL). Here we report that lymphomas with striking similarities to BL develop in mice bearing a(More)
The B cell-specific enzyme activation-induced cytidine deaminase (AID) has been shown to be essential for isotype switching and affinity maturation of antibody genes during the immune response. Conversely, AID activity has also been linked to autoimmunity and tumorigenesis. Determining how AID expression is regulated in vivo is therefore central to(More)
Murine models of human carcinogenesis are exceedingly valuable tools to understand genetic mechanisms of neoplastic growth. The identification of recurrent chromosomal rearrangements by cytogenetic techniques serves as an initial screening test for tumour specific aberrations. In murine models of human carcinogenesis, however, karyotype analysis is(More)
Plasma cell neoplasms in humans comprise plasma cell myeloma, otherwise known as multiple myeloma, Ig deposition and heavy chain diseases, and plasmacytoma (PCT). A subset of PCT, designated extramedullary PCT, is distinguished from multiple myeloma and solitary PCT of bone by its distribution among various tissue sites but not the bone marrow.(More)
We used gene targeting in mice to insert a His(6)-tagged mouse c-Myc cDNA, Myc(His), head to head into the mouse immunoglobulin heavy-chain locus, Igh, just 5' of the intronic enhancer, Emu. The insertion of Myc(His) mimicked both the human t(8;14)(q24;q32) translocation that results in the activation of MYC in human endemic Burkitt lymphomas and the(More)
Multiple myeloma (MM) remains a largely incurable, genetically heterogeneous plasma-cell malignancy that contains - just like many other cancers - a small fraction of clonogenic stem cell-like cells that exhibit pronounced self-renewal and differentiation capacities, but also pronounced drug resistance. These MM stem cells (MMSCs) are a controversial but(More)
Spectral precision distance microscopy was utilized to detect small but nonetheless consistently present conformational differences between the immunoglobulin heavy-chain gene clusters (IgH) that reside on the two chromosome 12 homologues in all diploid cells of the mouse. The euclidian distance (i.e., the mean arithmetic three-dimensional [3-D] distance)(More)
The role of the micronutrient, selenium, in human cancers associated with chronic inflammations and persistent infections is poorly understood. Peritoneal plasmacytomas (PCTs) in strain BALB/c (C), the premier experimental model of inflammation-dependent plasma cell transformation in mice, may afford an opportunity to gain additional insights into the(More)
Repair of DNA double strand breaks (DSB), either by homologous recombination (HR) or nonhomologous end-joining (NHEJ), is essential to maintain genomic stability. To examine the impact of NHEJ deficiency on genomic integrity in Ku80 null (Ku-) mice, the chromosomally integrated shuttle vector pUR288, which includes a lacZ reporter gene, was used to measure(More)