Zhang, Jun et al. (2009) International Worm Meeting "A C. elegans Kruppel-like factor, KLF3 acts on fatty acid synthesis related signal transduction pathway to regulate their activity."

Hashmi, Sarwar, Zhang, Jun, Huang, Chen-Han, Gaugler, Randy, Yang, Chuan, Brey, Christopher

[International Worm Meeting, 2009]

Type 2 diabetes (T2D) is a system disease involving changes in both conserved cores (pathway/network of glucose/lipid metabolism) and adaptive conduits for nutrient (food) intake, storage, and sensing. In full-blown T2D, insulin resistance and b-cell failure emerge owing to chronic pathogenic insults to metabolic networks and enduring perturbations of energy homeostasis. The family of Kruppel-like factors (KLFs), a conserved and important class of transcription factors, has been implicated to regulate lipogenesis and adipocyte differentiation in mammals. However, how fat storage is coordinated in response to positive and negative feedback signals is still poorly understood. To address mechanisms underlying fat storage we study a Caenorhabditis elegans Kruppel-like transcription factor, Ce-klf-3 and demonstrate that KLF-3 is a key regulator of fat metabolism in C. elegans. The Ce-klf-3 is highly expressed during worm''s development and predominantly present in intestine, the site for fat digestion, absorption, storage, and utilization. We found a strong positive correlation between klf-3 expression and a change in fat deposition in worm''s intestine. Significantly, a klf-3(ok1975) loss-of-function mutation, characterized by 1.6 kb deletion spanning exon 2 to 3, increased fat accumulation in the intestine and caused severe defects in worm''s reproduction. Although klf-3 mutants seemed grossly similar to wild-type worms in appearance and in life span, they became completely sterile toward adulthood. Notably, mutant worms displayed extensive deposition of large amount of fat in the intestine, implicating a causal link of fat accumulation to reduce fertility. Our study also demonstrates that KLF-3 is critical for maintaining normal fatty acid composition and it does so by regulating genes involved in fatty acid desaturation pathway. Strikingly, klf-3 mutant animals also impaired expression of genes devoted to fatty acid b-oxidation pathways. We present the first clear in vivo evidence supporting essential regulatory roles for KLF-3 in fat storage linking fat metabolism and reproduction in C. elegans. Such a casual relationship in the worm opens up a window to look into comparable disease states in human diabetes, i.e., obesity-conditioned insulin resistance and lipotoxicity-induced b-cell failure.

Gissendanner CR et al. (2014) Genesis "C. elegans nuclear receptor NHR-6 functionally interacts with the jun-1 transcription factor during spermatheca development."

Praslicka B, El Sayed M, Cardin D, Harmson JS, Rowan BG, Gissendanner CR, Dubose CJ

[Genesis, 2014]

The NR4A nuclear receptor NHR-6 is an essential regulator of spermatheca organogenesis in C. elegans. In this study, we perform a focused, RNAi-based screen to identify modifiers of partial nhr-6 loss of function. Ninety-eight genes that encode signaling proteins expressed in the spermatheca were screened for enhancement of the nhr-6 RNAi phenotype. We identify the C. elegans gene jun-1, which encodes the homolog of the Jun transcription factor, as a strong enhancer of nhr-6 partial loss of function. We show that nhr-6 and jun-1 function together to regulate development of the spermatheca and are necessary for generating an organ with the normal number of cells. jun-1 is expressed in all cells of the developing spermatheca. We also provide evidence that NHR-6 and JUN-1 can physically interact in a yeast two-hybrid assay. Our results provide in vivo evidence that NR4A nuclear receptor and Jun transcription factor interactions are essential in regulating developmental processes in metazoans.

Hiatt SM et al. (2009) Mol Biol Cell "Caenorhabditis elegans FOS-1 and JUN-1 regulate plc-1 expression in the spermatheca to control ovulation."

Matsumoto K, Kerppola TK, Ellis RE, Shyu YJ, Hiatt SM, Hisamoto N, Duren HM, Hu CD, Kariya KI

[Mol Biol Cell, 2009]

Fos and Jun are components of activator protein-1 (AP-1) and play crucial roles in the regulation of many cellular, developmental, and physiological processes. Caenorhabditis elegans fos-1 has been shown to act in uterine and vulval development. Here, we provide evidence that C. elegans fos-1 and jun-1 control ovulation, a tightly regulated rhythmic program in animals. Knockdown of fos-1 or jun-1 blocks dilation of the distal spermathecal valve, a critical step for the entry of mature oocytes into the spermatheca for fertilization. Furthermore, fos-1 and jun-1 regulate the spermathecal-specific expression of plc-1, a gene that encodes a phospholipase C (PLC) isozyme that is rate-limiting for inositol triphosphate production and ovulation, and overexpression of PLC-1 rescues the ovulation defect in fos-1(RNAi) worms. Unlike fos-1, regulation of ovulation by jun-1 requires genetic interactions with eri-1 and lin-15B, which are involved in the RNA interference pathway and chromatin remodeling, respectively. At least two isoforms of jun-1 are coexpressed with fos-1b in the spermatheca, and different AP-1 dimers formed between these isoforms have distinct effects on the activation of a reporter gene. These findings uncover a novel role for FOS-1 and JUN-1 in the reproductive system and establish C. elegans as a model for studying AP-1 dimerization.

Irazoqui JE (2015) Immunity "Why worms watch their hemidesmosomes and why you should, too."

Irazoqui JE

[Immunity, 2015]

Hemidesmosomes are cellular attachment structures of great importance to the epidermis. In this issue of Immunity, Zhang et al. (2015) have discovered that in addition to having structural functions, invertebrate and human hemidesmosomes are actively monitored by the cell as a novel mechanism for detecting pathogenic infection.

Susan M Fox et al. (2004) Mid-west Worm Meeting "Identification and characterization of C. elegans Fos and Jun homologs"

Chang-Deng Hu, Elizabeth J Taparowsky, Tom K Kerppola, Alfred Zullo, Ronald E Ellis, Susan M Fox, Soochin Cho

[Mid-west Worm Meeting, 2004]

The basic region leucine zipper (bZIP) proteins constitute of one of the largest families of transcription factors in mammals, Drosophila , C. elegans and plants. They bind to specific DNA sequences as heterodimers or homodimers , and regulate a variety of cellular processes. For example, the activator protein 1 (AP-1) group of bZIP proteins contains the Fos , Jun, ATF2 and Maf subfamilies, which bind to the AP-1 consensus sequences. AP-1 proteins activate a variety of target genes that regulate cellular proliferation, differentiation and death, as well as stress responses. Furthermore, genetic analyses using mouse and Drosophila have revealed that AP-1 proteins play pivotal roles in regulating specific developmental events. P> P> How do bZIP proteins form the correct heterodimers and homodimers at appropriate times during development, out of many other possible combinations? We are developing C. elegans as a system to answer this question. First, we searched the C. elegans genome sequence database and identified 21 unique bZIP-containing proteins. Sequence alignment and phylogenetic analysis of the bZIP domains along with those of Drosophila and human bZIP proteins showed that the proteins encoded by F29G9.4 and T24H10.2 are the closest homologs of Drosophila and human Fos and Jun, respectively. We tentatively name these genes Ce-fos-1 and Ce-jun-1 . P> P> To determine whether these genes regulate specific developmental events in C. elegans , we used RNA interference. Initial studies suggest that Ce-fos-1 is required for normal vulva development, and Ce-jun-1 is required for embryonic viability. To characterize their DNA-binding ability and dimerization selectivity, we carried out gel mobility shift assays, and found that they bind AP-1 consensus sequences as a heterodimer . As is the case with mammalian Fos and Jun proteins, Ce-JUN-1 can also form homodimers , but Ce-FOS-1 cannot. Furthermore, both Ce-FOS-1 and Ce-JUN-1 could form heterodimers with rat c-Fos to bind DNA, suggesting that they are functionally interchangeable in terms of DNA binding. Finally, these interactions have been confirmed in living cells and in living animals using a bimolecular fluorescence complementation ( BiFC ) assay. Taken together, our results strongly suggest that Ce-FOS-1 and Ce-JUN-1 are the C. elegans Fos and Jun proteins, and that these genes play important roles in C. elegans development. Our ability to assay dimerization in vivo should allow us to elucidate how their pattern of dimerization changes during development.

Kumsta C et al. (2019) J Cell Biol "Getting under the skin: Cuticle damage elicits systemic autophagy response in C. elegans."

Hansen M, Kumsta C

[J Cell Biol, 2019]

In this issue, Zhang et al. (2019. <i>J. Cell. Biol.</i> https://doi.org/10.1083/jcb.201907196) describe a molecular mechanism by which cuticular damage in the nematode <i>C. elegans</i> leads to systemic induction of autophagy by signals propagated from sensory neurons via the TGF- signaling pathway.

Svendsen JM et al. (2018) Dev Cell "piRNA Rules of Engagement."

Svendsen JM, Montgomery TA

[Dev Cell, 2018]

piRNAs are known to silence transposable elements, but not all piRNAs match transposon sequences. Recent studies from Shen etal. (2018) and Zhang etal. (2018) identify rules for piRNA target recognition in Caenorhabditis elegans. Permissive pairing rules allow targeting of essentially all germline mRNAs, while protective mechanisms prevent silencing self-genes.

Susan M Fox et al. (2005) International Worm Meeting "Identification and Characterization of C. elegans Fos and Jun Homologs"

John Shyu, Elizabeth J Taparowsky, Ronald E Ellis, Tom K Kerppola, Susan M Fox, Soochin Cho, Susan Strome, Alfred Zullo, Chang-Deng Hu

[International Worm Meeting, 2005]

The basic region leucine zipper (bZIP) proteins constitute one of the largest families of transcription factors in mammals, Drosophila, and C. elegans. These proteins function as dimers to bind specific DNA sequences and regulate a variety of cellular processes. For example, the activator protein 1 (AP-1) group of bZIP proteins, containing Fos, Jun, ATF2 and Maf subfamilies bind AP-1 consensus sequences and activate a variety of target genes that regulate cellular proliferation, differentiation and death, as well as stress responses. Furthermore, genetic analyses using mice and Drosophila have revealed that AP-1 proteins play pivotal roles in regulating specific developmental events. How do bZIP proteins chose the correct partner for a specific heterodimer or homodimer at appropriate times during development? We are developing C. elegans as a system to answer this. Following identification of 24 unique bZIP proteins, sequence alignment and phylogenetic analysis of the C. elegans bZIP domains along with those of Drosophila and human bZIP proteins showed that the proteins encoded by F29G9.4 and T24H10.7 are the closest homologs of Drosophila and human Fos and Jun, respectively. We tentatively named these genes Ce-fos-1 and Ce-jun-1. Using RNA interference, we have found that Ce-fos-1 is required for fertility, as 95% of offspring were sterile. Observation of native expression patterns is underway, using GFP fusion constructs, antibody staining and in situ hybridization. We have found that the bZIP regions of Ce-FOS-1 and Ce-JUN-1 bind AP-1 consensus sequences as a heterodimer, and Ce-JUN-1 can bind as a homodimer. These interactions have been confirmed in living cells and in living worms using the bimolecular fluorescence complementation (BiFC) assay, a novel approach used to visualize protein-protein interactions. The identification of native promoters of Ce-fos-1 and Ce-jun-1 and the visualization of the temporal and spatial interactions of Ce-FOS-1 and Ce-JUN-1 are underway.

McDiarmid, Troy A et al. (2020) MicroPubl Biol

Kepler, Lexis D, McDiarmid, Troy A, Rankin, Catharine H

[MicroPubl Biol, 2020]

The Auxin-Inducible Degradation (AID) system is a powerful technique in the C. elegans toolkit that enables conditional and reversible protein depletion with high temporal and spatial specificity (Zhang et al. 2015; Martinez et al. 2020; Ashley et al. 2020; Martinez and Matus 2020). This system relies on tagging a gene of interest with a short AID degron sequence and transgenic expression of TIR1, an inducible E3 ubiquitin ligase normally found only in plants (Nishimura et al. 2009; Zhang et al. 2015). Upon exposure to the plant-derived hormone Auxin, TIR1 is activated and targets AID-tagged proteins for proteasomal degradation (Nishimura et al. 2009; Zhang et al. 2015) (Figure 1A). While there are qualitative reports that Auxin does not overtly affect the morphology or behavior of wild-type C. elegans (Zhang et al. 2015), this has not been quantitatively assessed. Determining whether Auxin significantly affects C. elegans morphology and behavior, even in subtle ways, is important given the C. elegans communitys rapid uptake of the AID system (Kasimatis et al. 2018; Nance and Frkjr-Jensen 2019; Ashley et al. 2020; McDiarmid et al. 2020). Here, we use our high-throughput machine vision tracking system, the Multi-Worm Tracker (MWT) (Swierczek et al. 2011), to investigate whether exposure to Auxin affects a suite of morphological, locomotor, mechanosensory, and short-term habituation learning phenotypes in our labs derivate of Bristol N2 wild-type worms and the CGC wild-type reference strain, PD1074 (Yoshimura et al. 2019) (Figure 1B).

Kavita S Oommen et al. (2005) International Worm Meeting "Crosstalk between Notch and Fos/Jun during specification of a uterine cell fate"

Kavita S Oommen, Anna P Newman

[International Worm Meeting, 2005]

One signaling pathway alone can specify numerous yet distinct cell fates during development. Additional mechanisms must be in place to ensure that reiteratively utilized pathways can achieve specificity. In C. elegans, evolutionarily conserved LIN-12/Notch signaling in the developing ventral uterus establishes the cell fate. The cells undergo a well-characterized lineage and differentiate into cell types that form a proper uterine-vulval connection critical for egg laying. The SOX domain transcription factor encoded by egl-13 is specifically expressed in the cells from the time of specification through differentiation and morphogenesis. Through deletional analysis of the upstream regulatory sequences (URS) of an egl-13 transcriptional gene fusion, we deduced a minimal regulatory region critical for driving -specific expression of egl-13. Furthermore, we deleted discrete, highly conserved binding sites within this defined region to pinpoint which cis factor(s) may be relevant for transcriptional regulation of egl-13. In this manner, we isolated a single binding site for LAG-1, a member of the CSL (CBF-1/Su(H)/LAG-1) family of DNA binding proteins known to mediate Notch signaling, that is required for egl-13 expression at the time of cell specification. To our surprise, we discovered that a conserved binding site for the dimeric Fos/Jun proteins is also required for egl-13 expression at specification as well. Fos and Jun proteins constitute a subclass of basic domain leucine zipper transcription factors characterized as oncogenes in mammals. In addition, both sites are necessary for cDNA-mediated rescue of egl-13 mutants. Observations including RNAi of Fos/Jun homologs and genetic mutant characterization of the closest C. elegans Fos homolog support the involvement of Fos/Jun factors in normal uterine development and egl-13 expression. We have conducted in vitro assays to identify the corresponding Jun factor(s) and confirmed direct binding of FOS/JUN proteins to their respective binding site within the egl-13 URS. This study is the first to elucidate a cooperative regulatory mechanism between LIN-12/Notch and Fos/Jun pathways and may explain how Notch signaling in C. elegans is able to establish a distinct cell fate in the cell paradigm.