Identification of LMO2 transcriptome and interactome in diffuse large B-cell lymphoma

LMO2 regulates gene expression facilitating the formation of multipartite DNA-binding complexes. In B cells, LMO2 is specifically up-regulated in the Germinal Center (GC) reaction and is expressed in GC-derived non-Hodgkins lymphomas. LMO2 is one of the most powerful prognostic indicators in DLBCL patients. However, its function in GC B cells and DLBCL is currently unknown. In the present study we characterized the LMO2 transcriptome and interactome in DLBCL cells. LMO2 regulates genes implicated in kinetochore function, chromosome assembly and mitosis. Overexpression of LMO2 in DLBCL cell lines results in centrosome amplification. In DLBCL, the LMO2 complex contains some of the traditional partners such as LDB1, E2A, HEB, Lyl1, ETO2 and SP1, but not TAL1 or GATA proteins. Furthermore, we identified novel LMO2 interacting partners: ELK1, NFATc1 and LEF-1 proteins. Reporter assays revealed that LMO2 increases transcriptional activity of NFATc1 and decreases transcriptional activity of LEF-1 proteins. Overall, our studies identified a novel LMO2 transcriptome and interactome in DLBCL and provide a platform for future elucidation of LMO2 function in GC B-cells and DLBCL pathogenesis.

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Cubedo E, Gentles AJ, Huang C, Natkunam Y, Bhatt S, Lu X, Jiang X, Romero-Camarero I, Freud A, Zhao S, Bacchi CE, Martínez-Climent JA, Sánchez-García I, Melnick A, Lossos IS