Article

The Ewing’s sarcoma EWS/FLI-1 fusion gene encodes a more potent transcriptional activator and is a more powerful transforming gene than FLI-1

Department of Pediatrics, Gwynne Hazen Cherry Memorial Laboratories, University of California, Los Angeles.
Molecular and Cellular Biology (Impact Factor: 5.04). 01/1994; 13(12):7393-8. DOI: 10.1128/MCB.13.12.7393
Source: PubMed

ABSTRACT EWS/FLI-1 is a chimeric protein formed by a tumor-specific 11;22 translocation found in both Ewing's sarcoma and primitive neuroectodermal tumor of childhood. EWS/FLI-1 has been shown to be a potent transforming gene, suggesting that it plays an important role in the genesis of these human tumors. We now demonstrate that EWS/FLI-1 has the characteristics of an aberrant transcription factor. Subcellular fractionation experiments localized the EWS/FLI-1 protein to the nucleus of primitive neuroectodermal tumor cells. EWS/FLI-1 specifically bound in vitro an ets-2 consensus sequence similarly to normal FLI-1. When coupled to a GAL4 DNA-binding domain, the amino-terminal EWS/FLI-1 region was a much more potent transcriptional activator than the corresponding amino-terminal domain of FLI-1. Finally, EWS/FLI-1 efficiently transformed NIH 3T3 cells, but FLI-1 did not. These data suggest that EWS/FLI-1, functioning as a transcription factor, leads to a phenotype dramatically different from that of cells expressing FLI-1. EWS/FLI-1 could disrupt normal growth and differentiation either by more efficiently activating FLI-1 target genes or by inappropriately modulating genes normally not responsive to FLI-1.

Download full-text

Full-text

Available from: Michael J Klemsz, Aug 13, 2015
0 Followers
 · 
117 Views
  • Source
    • "In the basal state, endogenous EWS interacted weakly with YBX1 (Figure 3A, middle panels), but following short adipogenic stimulation (4h), the EWS-YBX1 interaction was greatly enhanced (Figure 3A, lower panels). EWS encodes a potent transactivation domain in the amino-terminus (May et al., 1993) and is frequently involved in chromosomal translocations that generate aberrant transcription factors (Sankar and Lessnick, 2011). Thus, we tested the effects of EWS on the transcriptional regulation of Bmp7 using a 1395-bp (-1392 to +3) mouse Bmp7 promoterreporter construct that contains an YBX1-binding site in the proximal region (-192 to +3) (Wang and Hirschberg, 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The recent surge in obesity has provided an impetus to better understand the mechanisms of adipogenesis, particularly in brown adipose tissue (BAT) because of its potential utilization for antiobesity therapy. Postnatal brown adipocytes arise from early muscle progenitors, but how brown fat lineage is determined is not completely understood. Here, we show that a multifunctional protein, Ewing Sarcoma (EWS), is essential for determining brown fat lineage during development. BATs from Ews null embryos and newborns are developmentally arrested. Ews mutant brown preadipocytes fail to differentiate due to loss of Bmp7 expression, a critical early brown adipogenic factor. We demonstrate that EWS, along with its binding partner Y-box binding protein 1 (YBX1), activates Bmp7 transcription. Depletion of either Ews or Ybx1 leads to loss of Bmp7 expression and brown adipogenesis. Remarkably, Ews null BATs and brown preadipocytes ectopically express myogenic genes. These results demonstrate that EWS is essential for early brown fat lineage determination.
    Developmental Cell 08/2013; 26(4):393-404. DOI:10.1016/j.devcel.2013.07.002 · 10.37 Impact Factor
  • Source
    • "Initial clues about the role of the FET proteins in gene transcription came from the observation that their N-terminal SYGQ-rich domain functions as a potent transcriptional activation domain in oncogenic fusion proteins (Bertolotti et al., 1999; May et al., 1993; Prasad et al., 1994; Zinszner et al., 1994). Moreover, the Drosophila homologue of FUS, named Cabeza (CAZ) or Sarcoma-associated RNA binding fly homologue (SARFH), was found to localize to areas of active transcription in polytene chromosomes of salivary glands (Immanuel et al., 1995). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Fused in sarcoma (FUS) is a nuclear DNA/RNA binding protein that regulates different steps of gene expression, including transcription, splicing and mRNA transport. FUS has been implicated in neurodegeneration, since mutations in FUS cause familial amyotrophic lateral sclerosis (ALS-FUS) and lead to the cytosolic deposition of FUS in the brain and spinal cord of ALS-FUS patients. Moreover, FUS and two related proteins of the same protein family (FET family) are co-deposited in cytoplasmic inclusions in a subset of patients with frontotemporal lobar degeneration (FTLD-FUS). Cytosolic deposition of these otherwise nuclear proteins most likely causes the loss of a yet unknown essential nuclear function and/or the gain of a toxic function in the cytosol. Here we summarize what is known about the physiological functions of the FET proteins in the nucleus and cytoplasm and review the distinctive pathomechanisms that lead to the deposition of only FUS in ALS-FUS, but all three FET proteins in FTLD-FUS. We suggest that ALS-FUS is caused by a selective dysfunction of FUS, while FTLD-FUS may be caused by a dysfunction of the entire FET family.
    Molecular and Cellular Neuroscience 04/2013; 56. DOI:10.1016/j.mcn.2013.03.006 · 3.73 Impact Factor
  • Source
    • "In ES, copy number changes were low in any given tumor sample lending credence to the primary translocation in ES being a single major genetic hit of great import in development and maintenance of tumors. This supports studies on cultured human ES cells in which knockdown of EWS–FLI expression was shown to be sufficient to reverse transformation and tumorigenic properties (May et al., 1993). As stated earlier, however, EWS–FLI1 expression is likely not the only genetic or epigenetic hit that is required for development and maintenance of ES (Lessnick et al., 2002; Castillero-Trejo et al., 2005). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Ewing sarcoma (ES) is the second most common bone tumor affecting primarily adolescents and young adults. Despite recent advances in biological understanding, intensification of chemotherapeutic treatments, and progress in local control with surgery and/or radiation therapy, patients with metastatic or recurrent ES continue to have a dismal prognosis with less than 20% overall survival. All ES is likely metastatic at diagnosis although our methods of detection and classification may not account for this. Progressive disease may arise via a combination of: (1) selection of chemotherapy-resistant clones in primary tumor, (2) signaling from bone or lung microenvironments that may attract tumor cells to distant locations, and/or (3) genetic changes within the ES cells themselves due to DNA-damaging chemotherapeutic agents or other "hits." These possibilities and the evidence base to support them are explored.
    Frontiers in Oncology 01/2012; 2:2. DOI:10.3389/fonc.2012.00002
Show more