U19/Eaf2 knockout causes lung adenocarcinoma, B-cell lymphoma, hepatocellular carcinoma and prostatic intraepithelial neoplasia

Studies have attributed several functions to the Eaf family, including tumor suppression and eye development. Given the potential association between cancer and development, we set forth to explore Eaf1 and Eaf2/U19 activity in vertebrate embryogenesis, using zebrafish. In situ hybridization revealed similar eaf1 and eaf2/u19 expression patterns. Morpholino-mediated knockdown of either eaf1 or eaf2/u19 expression produced similar morphological changes that could be reversed by ectopic expression of target or reciprocal-target mRNA. However, combination of Eaf1 and Eaf2/U19 (Eafs)-morpholinos increased the severity of defects, suggesting that Eaf1 and Eaf2/U19 only share some functional redundancy. The Eafs knockdown phenotype resembled that of embryos with defects in convergence and extension movements. Indeed, knockdown caused expression pattern changes for convergence and extension movement markers, whereas cell tracing experiments using kaeda mRNA showed a correlation between Eafs knockdown and cell migration defects. Cardiac and pancreatic differentiation markers revealed that Eafs knockdown also disrupted midline convergence of heart and pancreatic organ precursors. Noncanonical Wnt signaling plays a key role in both convergence and extension movements and midline convergence of organ precursors. We found that Eaf1 and Eaf2/U19 maintained expression levels of wnt11 and wnt5. Moreover, wnt11 or wnt5 mRNA partially rescued the convergence and extension movement defects occurring in eafs morphants. Wnt11 and Wnt5 converge on rhoA, so not surprisingly, rhoA mRNA more effectively rescued defects than either wnt11 or wnt5 mRNA alone. However, the ectopic expression of wnt11 and wnt5 did not affect eaf1 and eaf2/u19 expression. These data indicate that eaf1 and eaf2/u19 act upstream of noncanonical Wnt signaling to mediate convergence and extension movements. EAF1 (ELL-associated factor 1) was first discovered through its ability to associate with the protein ELL (eleven-nineteen lysine-rich leukemia), a fusion partner of MLL in the t(11; 19)(q23;p13.1) chromosomal translocation associated with acute myeloid leukemia (1, 2). Subsequent studies found a second binding partner for ELL, EAF2, which was independently identified as an androgen up-regulated gene in the rat prostate and named human up-regulated 19 (U19) (3, 4). ELL binds to RNA polymerase II and acts as a transcriptional elongation factor whose targeted deletion leads to embryonic lethality in mice (5, 6). Both EAF1 and EAF2, which share significant sequence homology, stimulate ELL elongation activity (7). Studies by Luo et al. (8) argued that EAF proteins are important in MLL-ELL leukemogenesis, whereas our previous studies showed that EAF2/U19 inhibits xenograft prostate tumor growth and undergoes down-regulation in prostate cancer cell lines (9). These findings link the EAF2/U19 gene with two major human cancers: prostate cancer and acute myeloid leukemia. To investigate the function EAF2/U19 in vivo, we constructed a murine knock-out model. The EAF2...

Section: Discussionmentioning

confidence: 68%

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confidence: 82%

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Zebrafish eaf1 and eaf2/u19 Mediate Effective Convergence and Extension Movements through the Maintenance of wnt11 and wnt5 Expression

Liu¹,

Hu²,

Wang

et al. 2009

“…Moreover, our studies provided evidence that ELL alone has transactivation capability (32). In vitro and in vivo studies revealed U19/Eaf2 as a potential tumor suppressor (31,35), further supporting a role for ELL in tumor progression.…”

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confidence: 65%

Elongation Factor ELL (Eleven-Nineteen Lysine-rich Leukemia) Acts as a Transcription Factor for Direct Thrombospondin-1 Regulation

Zhou

Feng

Ban

et al. 2009

The eleven-nineteen lysine-rich leukemia (ELL) gene undergoes translocation and fuses in-frame to the multiple lineage leukemia gene in a substantial proportion of patients suffering from acute forms of leukemia. Studies show that ELL indirectly modulates transcription by serving as a regulator for transcriptional elongation as well as for p53, U19/Eaf2, and steroid receptor activities. Our in vitro and in vivo data demonstrate that ELL could also serve as a transcriptional factor to directly induce transcription of the thrombospondin-1 (TSP-1) gene. Experiments using ELL deletion mutants established that full-length ELL is required for the TSP-1 up-regulation and that the transactivation domain likely resides in the carboxyl terminus. Moreover, the DNA binding domain may localize to the first 45 amino acids of ELL. Not surprisingly, multiple lineage leukemia-ELL, which lacks these amino acids, did not induce expression from the TSP-1 promoter. In addition, the ELL core-response element appears to localize in the ؊1426 to ؊1418 region of the TSP-1 promoter. Finally, studies using zebrafish confirmed that ELL regulates TSP-1 mRNA expression in vivo, and ELL could inhibit zebrafish vasculogenesis, at least in part, through up-regulating TSP-1. Given the importance of TSP-1 as an anti-angiogenic protein, our findings may have important ramifications for better understanding cancer. ELL4 was first identified in acute myeloid leukemia as a translocation partner of MLL (1). Wild-type MLL positively regulates expression of Hox genes, important in embryonic development and hematopoiesis (2-4), but the formation of MLL chimeras dysregulates this expression, contributing to leukemogenesis (4 -14). MLL partners also likely contribute to leukemogenesis. One such partner is ELL, which fuses with MLL as a result of the frequent translocation event t(11;19) (q23; p13.1) that occurs in acute myeloid leukemia (1). In vitro studies showed that wild-type ELL can increase the rate of polymerase II transcriptional elongation by suppressing transient pausing (15,16), an activity shared by the two paralogs of ELL found in mammalian cells, ELL2 and ELL3 (17,18). The targeted knockout of ELL in mice caused embryonic lethality, suggesting an essential role for this protein in early embryonic development (19). Further functional analyses revealed that ELL regulates cell growth and survival (20) and serves as a selective co-regulator for steroid receptor functions (21). In all, these studies point to the importance of ELL in normally functioning cells.Like other MLL translocation products, the chimera MLL-ELL appears to play an important role in leukemogenesis (22,23). The MLL-ELL fusion product contains the amino-terminal region of MLL fused to amino acids 46 -621 of ELL that include the elongation domain and a lysine-rich region (1). Transplantation of blood progenitor cells transduced with MLL-ELL into sublethally irradiated normal mice resulted in morphological and clinical disease manifestations closely resembling those observed in pa...

“…The EAF2 locus exhibits frequent allelic loss in ϳ80% of advanced clinical prostate cancer specimens, and evidence for homozygous deletion also exists (1). EAF2 deficiency in mice leads to carcinogenesis in multiple tissues (2) as well as aspermatogenesis and reduced survival (3). In addition to EAF2, mammals also express EAF1, a protein that shares 58% identity and 74% similarity with EAF2.…”

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confidence: 99%

Regulation of Fertility, Survival, and Cuticle Collagen Function by the Caenorhabditis elegans eaf-1 and ell-1 Genes

Cai

Phong

Fisher

et al. 2011

EAF2, an androgen-regulated protein, interacts with members of the ELL (eleven-nineteen lysine-rich leukemia) transcription factor family and also acts as a tumor suppressor. Although these proteins control transcriptional elongation and perhaps modulate the effects of other transcription factors, the mechanisms of their actions remain largely unknown. To gain new insights into the biology of the EAF2 and ELL family proteins, we used Caenorhabditis elegans as a model to explore the in vivo roles of their worm orthologs. Through the use of transgenic worms, RNAi, and an eaf-1 mutant, we found that both genes are expressed in multiple cell types throughout the worm life cycle and that they play important roles in fertility, survival, and body size regulation. ELL-1 and EAF-1 likely contribute to these activities in part through modulating cuticle synthesis, given that we observed a disrupted cuticle structure in ell-1 RNAi-treated or eaf-1 mutant worms. Consistent with disruption of cuticle structure, loss of either ELL-1 or EAF-1 suppressed the rol phenotype of specific collagen mutants, possibly through the control of dpy-3, dpy-13, and sqt-3 collagen gene expression. Furthermore, we also noted the regulation of collagen expression by ELL overexpression in PC3 human prostate cancer cells. Together, these results reveal important roles for the eaf-1 and ell-1 genes in the regulation of extracellular matrix components.Androgens play a key role in prostate development, prostate cancer, and benign prostatic hyperplasia. Thus, identification and characterization of androgen-responsive genes could significantly contribute to the prevention and treatment of prostate cancer and benign prostatic hyperplasia. One such androgen-responsive gene is EAF2 (ELL-associated factor 2), which may serve as a tumor suppressor (1). The EAF2 locus exhibits frequent allelic loss in ϳ80% of advanced clinical prostate cancer specimens, and evidence for homozygous deletion also exists (1). EAF2 deficiency in mice leads to carcinogenesis in multiple tissues (2) as well as aspermatogenesis and reduced survival (3). In addition to EAF2, mammals also express EAF1, a protein that shares 58% identity and 74% similarity with EAF2. Both EAF proteins interact with the ELL family of transcription elongation factors, including ELL, ELL2, and ELL3 (4 -9). ELL has been identified in an array of species, including yeast (10), Drosophila (11), zebrafish (12), mouse (13), and human (14). This widely expressed gene is essential for embryonic development because deletion of ELL in mouse or Drosophila causes embryonic lethality (15,16). ELL also plays an important role in leukemia (8,17). Chromosomal translocation can lead to fusion of ELL with the MLL (multiple lineage leukemia) gene, and the MLL-ELL fusion protein can cause acute myeloid leukemia (8,18).The mechanisms of EAF/ELL action appear to be complex and involve multiple signaling pathways. ELL family proteins interact with RNA polymerase II and act as a transcription elongation factor (4, 19). Eisse...