Sumoylated NHR-25/NR5A Regulates Cell Fate during C. elegans Vulval Development

Abstract

Individual metazoan transcription factors (TFs) regulate distinct sets of genes depending on cell type and developmental or physiological context. The precise mechanisms by which regulatory information from ligands, genomic sequence elements, co-factors, and post-translational modifications are integrated by TFs remain challenging questions. Here, we examine how a single regulatory input, sumoylation, differentially modulates the activity of a conserved C. elegans nuclear hormone receptor, NHR-25, in different cell types. Through a combination of yeast two-hybrid analysis and in vitro biochemistry we identified the single C. elegans SUMO (SMO-1) as an NHR-25 interacting protein, and showed that NHR-25 is sumoylated on at least four lysines. Some of the sumoylation acceptor sites are in common with those of the NHR-25 mammalian orthologs SF-1 and LRH-1, demonstrating that sumoylation has been strongly conserved within the NR5A family. We showed that NHR-25 bound canonical SF-1 binding sequences to regulate transcription, and that NHR-25 activity was enhanced in vivo upon loss of sumoylation. Knockdown of smo-1 mimicked NHR-25 overexpression with respect to maintenance of the 3° cell fate in vulval precursor cells (VPCs) during development. Importantly, however, overexpression of unsumoylatable alleles of NHR-25 revealed that NHR-25 sumoylation is critical for maintaining 3° cell fate. Moreover, SUMO also conferred formation of a developmental time-dependent NHR-25 concentration gradient across the VPCs. That is, accumulation of GFP-tagged NHR-25 was uniform across VPCs at the beginning of development, but as cells began dividing, a smo-1-dependent NHR-25 gradient formed with highest levels in 1° fated VPCs, intermediate levels in 2° fated VPCs, and low levels in 3° fated VPCs. We conclude that sumoylation operates at multiple levels to affect NHR-25 activity in a highly coordinated spatial and temporal manner.

Nuclear receptor NR5A2 is involved in the calreticulin gene regulation during renal fibrosis

“…NR5A2 can be a target of SUMOylation by known ligases [23] and this reversible post-translational modification may lead to important alterations in the transcriptional activity of NR5A2. This has been documented in a variety of conditions, ranging from developmental regulation in C. elegans [29] and Drosophila [30] to antiinflammatory actions in the hepatic acute phase response [26] and hepatic reverse cholesterol transport [31]. Interestingly, SUMOylation of transcription factors may lead to decreased [26,31] or increased [32,33] transcriptional activity.…”

Defects in the C. elegans acyl-CoA Synthase, acs-3, and Nuclear Hormone Receptor, nhr-25, Cause Sensitivity to Distinct, but Overlapping Stresses

“…Use of an NHR-25 activity reporter [10] could allow monitoring of NHR-25 output in response to different stresses and genetic backgrounds. Tissue-specific RNA-seq coupled with NHR-25 ChIP-seq would allow determination of the gene regulatory network and determination of direct NHR-25 targets in specific cell-types, such as seam cells.…”

Rapid degradation ofC. elegansproteins at single-cell resolution with a synthetic auxin

“…We focused on a well-481 studied system of organogenesis, C. elegans uterine-vulval cell specification and 482 morphogenesis (Figure 1B) (Schindler and Sherwood 2013). As a proof-of-principle, we 483 chose to deplete the nuclear hormone receptor, nhr-25, a homolog of arthropod Ftz-F1 484 and vertebrate SF-1/NR5A1 and LRH-1/NR5A2, which has been shown to function 485 pleiotropically in a wide array of developmental events, from larval molting (Asahina et al 486 2000;Gissendanner and Sluder 2000;Frand et al 2005), heterochrony (Hada et al 23 2010), and uterine-vulval morphogenesis (Chen et al 2004;Hwang and Sternberg 2004;488 Asahina et al 2006;Hwang et al 2007;Ward et al 2013). It was this pleiotropy that made 489 targeting NHR-25 an attractive target, as RNAi and mutant analyses have shown 490 previously that it is initially required in the AC during the AC/VU decision for proper 491 specification of AC fate (Hwang and Sternberg 2004;Asahina et al 2006) and 492 approximately 7 hours later it is required in the underlying VPCs for cell division (Chen et 493 al.…”