Jonathan B. Weitzman

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To assess directly the functional role of the integrin VLA-3 (alpha 3 beta 1), we transfected human alpha 3 cDNA into erythroleukemia (K562) cells and rhabdomyosarcoma (RD) cells. The resulting transfectants (KA3 and RA3) expressed alpha 3 beta 1 on the cell surface as confirmed using a panel of nine anti-alpha 3 monoclonal antibodies. Neither of the(More)
Multi-gene families of transcription factors pose a formidable challenge to molecular and functional analysis. Dissecting distinct functions for individual family members requires a combination of approaches in different cellular and animal models. The AP-1 transcription factor complex serves as a paradigm for understanding the dynamics of transcriptional(More)
Complex links between infection and cancer suggest that we still can learn much about tumorigenesis by studying how infectious agents hijack the host cell machinery. We studied the effects of an intracellular parasite called Theileria that infects bovine leukocytes and turns them into invasive cancer-like cells. We investigated the host cells pathways that(More)
JunD is the most broadly expressed member of the Jun family and the AP-1 transcription factor complex. Primary fibroblasts lacking JunD displayed p53-dependent growth arrest, upregulated p19(Arf) expression, and premature senescence. In contrast, immortalized cell lines lacking JunD showed increased proliferation and higher cyclinD1 levels. These properties(More)
Various beta 1 integrins (VLA-2, VLA-3, VLA-4) have been suggested to bind directly to themselves or to each other, thus mediating cell-cell adhesion. Here we expressed the human alpha 2 and alpha 3 subunits in three different cell lines (human erythroleukemia K562, human rhabdomyosarcoma RD and Chinese hamster ovary CHO cells). Although cell surface alpha(More)
Upregulation of the matrix metalloproteinase (MMP)-9 plays a central role in tumor progression and metastasis by stimulating cell migration, tumor invasion, and angiogenesis. To gain insights into MMP-9 expression, we investigated its epigenetic control in a reversible model of cancer that is initiated by infection with intracellular Theileria parasites.(More)
Evidence is accumulating about the role of individual AP-1 components in cell proliferation and transformation. Notably, Ras-mediated transformation is characterized by the upregulation of particular AP-1 members, such as c-Jun and Fra-1. The p14/p19ARF tumor suppressor gene is a key link between oncogenic Ras signaling and the p53 pathway. We explored the(More)
Maintaining genome integrity and transmission of intact genomes is critical for cellular, organismal, and species survival. Cells can detect damaged DNA, activate checkpoints, and either enable DNA repair or trigger apoptosis to eliminate the damaged cell. Aberrations in these mechanisms lead to somatic mutations and genetic instability, which are hallmarks(More)
Here we describe a novel "antibody-redirected cell adhesion" (ARCA) assay. This assay measures heterotypic cell-cell adhesion, resulting from antibody bridging between Fc gamma receptors type II (CD32) on leukocytes, and clustered integrins on adherent cell monolayers. This ARCA activity, facilitated by integrins alpha3 beta1 or alpha4 beta1, required an(More)