The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.
Apoptosis and macrophage-mediated deletion of precursor B cells in the bone marrow of E mu-myc transgenic mice.
Transgenic mice expressing the c-myc proto-oncogene under the control of the Ig heavy chain enhancer (E mu-myc) all eventually develop clonal pre-B- or B-cell tumors. The preneoplastic period is characterized by increased polyclonal proliferation of pro-B and pre-B cells in the bone marrow (BM) associated with a reduced number of B cells, suggesting a high degree of B-cell loss. To examine the mechanisms of this cell loss, we have identified B220+ B-lineage cells within the BM of pretumorous E mu-myc transgenic mice by in vivo radiolabeling and electron microscope radioautography. Large mitotic B220(+)-labeled cells form prominent clusters in the extravascular compartment of the BM. Some B220+ small lymphocytes, as well as large lymphoid cells, enter BM sinusoids. However, in addition, large numbers of B220+ cells exhibit nuclear chromatin condensation, fragmentation, and other morphologic features characteristic of apoptotic cell death. Propidium iodide staining and flow cytometry of BM cells from pretumorous E mu-myc transgenic mice, as well as agarose gel electrophoresis of DNA, confirm extensive apoptosis. Many B220+ apoptotic cells are closely associated with the extensive processes of prominent macrophages that contain numerous B220+ apoptotic bodies and complex lysosomal systems. These results suggest that the constitutive expression of c-myc oncogene in BM B-lineage cells, which increases the proliferation of precursor B cells, also leads to increased apoptotic cell death and rapid elimination by resident macrophages. Further mutations may be needed to block these protective mechanisms and permit surviving c-myc-dysregulated cells to leave the BM and to initiate tumorigenesis.[1]References
- Apoptosis and macrophage-mediated deletion of precursor B cells in the bone marrow of E mu-myc transgenic mice. Jacobsen, K.A., Prasad, V.S., Sidman, C.L., Osmond, D.G. Blood (1994) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Use
