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

Abstract

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...

Identification of a genetic interaction between the tumor suppressor EAF2 and the retinoblastoma protein (Rb) signaling pathway in C. elegans and prostate cancer cells

“…ALF50 ( eaf-1(tm3976) ) was described previously [1]. ZH231 unc-76 ( e911 ) V ; enIs7 [ Pced-1 ced-1 :: GFP + unc-76 (+)] X [9] was generously provided by Zheng Zhou (Baylor College of Medicine, Houston, TX).…”

“…The EAF-1 protein forms a protein complex with the ELL ortholog ELL-1, and together these proteins control fertility, body size, and the expression of cuticle collagens in worms [1]. Despite these important functions, genetic deletion of the eaf-1 gene in the worm is not lethal but leads to a reduction in fertility, where eaf-1 mutants produce ~150 offspring instead of the normal 300.…”

Conditional deletion of ELL2 induces murine prostate intraepithelial neoplasia

“…In this study, Simone et al, showed that endogenous EAF2 coimmunoprecipitated with transfected ELL2 in 293 cells and that like the MLL-ELL fusion protein (Lavau, et al 2000), MLL-EAF2 could immortalize hematopoietic progenitor cells in vitro. Recently, eaf-1 and ell-1, worm orthologs of EAF1 , EAF2 and ELL1 and ELL2 , were shown to have overlapping function in the regulation of fertility, survival and cuticle formation in C. elegans (Cai, et al 2011). In advanced prostate cancer, EAF2 protein was down-regulated (Xiao, et al 2003; Ai, et al 2013; Pascal, et al 2013); and, overexpression of EAF2 in prostate cancer cell lines induced apoptosis and inhibited the growth of xenograft tumors (Xiao et al 2003).…”

RNA Polymerase II transcription elongation and Pol II CTD Ser2 phosphorylation

“…While C. elegans does contain homologs for a subset of the SEC components, specifically ELL1 (Y24D9A.1), AFF9 (Y55B1BR.1 and Y55B1BR.2), and EAF (D1007.16), these factors do not appear to play an essential role in transcription. 157 Furthermore, knock down of ELL and AFF9 does not significantly affect either Ser2-P levels or viability (E.A. Bowman, W.G.…”