Fasting induced changes in gene expression profiles of C. elegans
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ABSTRACT: Many species undergo sexual reproduction to distribute the parental genomes and increase the genomic diversity of the progeny. Among such species, sexual dimorphism is often displayed through morphology, size, behavior, and life-span, depending on the survival and reproduction strategies of the species. The nematode Caenorhabditis elegans has two sexes, hermaphrodite and male, and only the hermaphrodites, which produce both oocytes and sperm, are essential for the perpetuation of the species. In this study, we found that dietary restriction, which is the most reproducible way to retard aging in many species, extends the life-span of C. elegans hermaphrodites but not that of males. Our analysis revealed that fasting induces male-enriched genes in hermaphrodites and that the sex determination pathway affects life-span regulation, even after the completion of development, and is regulated by food availability. Furthermore, fasting activates the entire X-chromosome only in hermaphrodites. Our tiling array analysis identified a fasting-inducible, X-linked non-coding RNA for which expression positively correlated with the activation level of the X-chromosome and longevity. These links between the sex determination mechanism and dietary restriction at multiple levels may give priority to the survival of hermaphrodites during food shortages in C. elegans.
Project description:Intermittent fasting is one of the most effective dietary restriction regimens that extend life-span in C. elegans and mammals. Fasting-stimulus responses are key to the longevity response; however, the mechanisms that sense and transduce fasting-stimulus have remained largely unknown. Through a comprehensive transcriptome analysis in C. elegans, we have found that along with the FOXO transcription factor DAF-16, AP-1 (JUN-1/FOS-1) plays a central role in fasting-induced transcriptional changes. KGB-1, one of the C. elegans JNKs, acted as an activator of AP-1, and was activated in response to fasting. KGB-1 and AP-1 were involved in intermittent fasting-induced longevity. Fasting-induced upregulation of the components of the SCF E3 ubiquitin ligase complex via AP-1 and DAF-16 enhanced protein ubiquitination, and reduced protein carbonylation. Our results have thus identified a fasting-responsive KGB-1/AP-1 signaling pathway, which, together with DAF-16, causes transcriptional changes that mediate longevity partly through regulating proteostasis. We synchronized mek-1 and mlk-1 mutants and collected them at 2 day adult, and move them to the new plate with (Fed) or without food (Fasting). Two days later, we collected moved animals and extracted total RNA and subject them to microarray.
Project description:One of the most important issues in the study of aging is to discover compounds with longevity-promoting activity and to unravel their underlying mechanisms. Queen honey bees are continuously fed royal jelly (RJ), and they live more than 10 times longer than hive workers, derived from the same diploid genome, which are fed it only for a short period of time during their larval stages. Therefore, RJ is likely to contain longevity-promoting agents for queens. RJ has been reported to possess diverse pharmacological properties. Furthermore, protease-treated RJ (pRJ) has additional beneficial activities. How RJ and pRJ exert these effects and which components in them play a critical role is largely unknown. The evolutionally conserved mechanisms that control lifespan have been indicated. The nematode Caenorhabditis elegans has been widely used for study of aging and longevity, due to its relatively short lifespan and well-established genetic pathways. The purpose of the present study was to elucidate whether RJ and its related substances contain the life span-extending activity in C. elegans and to obtain some insight into the active agents and their mechanisms. We found that both RJ and pRJ extended the lifespan of C. elegans. The life span-extending activity of pRJ was enriched by ODS column chromatography (pRJ-Fraction 5). pRJ-Fr. 5 extended the life span partly by acting through the FOXO transcription factor DAF-16, the activation of which is known to promote longevity in C. elegans by reducing insulin/IGF-1 signaling (IIS). pRJ-Fr. 5 induced changes in the expression of 3 genes encoding insulin-like peptides. Moreover, pRJ-Fr. 5 and reduced IIS shared some common features in terms of their effect on gene expression, such as up-regulation of dod-3 and down-regulation of dod-19, dao-4 and fkb-4. The dod-19 is a previously identified life span determinant in C. elegans, and the fkb-4 encodes a homologue of the mammalian FK506-binding protein. 10-Hydroxy-2-decenoic acid (10-HDA), which was present in high concentration in pRJ-Fr. 5, increased the lifespan independently of DAF-16 activity.These results demonstrate that RJ and its related substances extended the life span in C. elegans, suggesting that RJ may contain longevity-promoting factors common to diverse species across phyla. pRJ-Fr. 5 had higher life span-extending activity than either RJ or pRJ and extended the life span in part through the IIS-DAF-16 pathway. We provide the first evidence that 10-HDA, a defined natural product in RJ, extended organismal lifespan. It is noteworthy that 10-HDA performed its lifespan-extending function through a mechanism totally different from the IIS-DAF-16 pathway. Further search and characterization of the lifespan-extending agents in RJ and pRJ may broaden our understanding of the gene network of longevity regulation in diverse species and provide the possibility for nutraceutical interventions in the aging process. C. elegans N2 hermaphrodites were untreated or treated with pRJ-Fr. 5 (25mg/ml) for 24 h starting at the larval 4 (L4) stage.
Project description:Intermittent fasting is one of the most effective dietary restriction regimens that extend life-span in C. elegans and mammals. Fasting-stimulus responses are key to the longevity response; however, the mechanisms that sense and transduce fasting-stimulus have remained largely unknown. Through a comprehensive transcriptome analysis in C. elegans, we have found that along with the FOXO transcription factor DAF-16, AP-1 (JUN-1/FOS-1) plays a central role in fasting-induced transcriptional changes. KGB-1, one of the C. elegans JNKs, acted as an activator of AP-1, and was activated in response to fasting. KGB-1 and AP-1 were involved in intermittent fasting-induced longevity. Fasting-induced upregulation of the components of the SCF E3 ubiquitin ligase complex via AP-1 and DAF-16 enhanced protein ubiquitination, and reduced protein carbonylation. Our results have thus identified a fasting-responsive KGB-1/AP-1 signaling pathway, which, together with DAF-16, causes transcriptional changes that mediate longevity partly through regulating proteostasis.
Project description:Sexual reproduction (meiosis and syngamy) is the major form of reproduction in diploid Boechera species, but most species hybrids reproduce by apomixis (unreduced gametophyte formation followed by parthenogenesis of the unreduced egg). In this study, we used Arabidopsis microarrays to detail global programs of gene expression underlying sexual and apomictic modes of reproduction.
Project description:The evolutionary paths taken by each sex within a given species sometimes diverge, resulting in behavioral differences. Given their distinct needs, the mechanism by which each sex learns from a shared experience is still an open question. Here, we reveal sexual dimorphism in learning: C. elegans males do not learn to avoid the pathogenic bacteria PA14 as efficiently and rapidly as hermaphrodites. Notably, neuronal activity following pathogen exposure was dimorphic: hermaphrodites generate robust representations while males, in line with their behavior, exhibit contrasting representations. Transcriptomic and behavioral analysis revealed that the neuropeptide receptor npr-5, an ortholog of the mammalian NPY receptor, regulates male learning by modulating neuronal activity. Furthermore, we show the dependency of the males’ decision-making on their sexual status and demonstrate the pivotal role of npr-5 as a modulator of incoming sensory cues. Taken together, we portray sex-specific plasticity in behavior toward a shared experience by modulating learning.
Project description:Schistosoma mansoni is a dioecious species, that is, it has two differentiated sexes. Interestingly, this sexual species evolved from a hermaphrodite ancestor. Indeed, most Platyhelminthes are hermaphrodites. Here we characterize the microRNAs of S. mansoni and quantify their differential expression between males and females.
Project description:This SuperSeries is composed of the following subset Series: GSE4093: Resveratrol treatment of daf-16 mutant C. elegans GSE4094: N2 worms treated with Resveratrol GSE4095: Sir-2.1 low copy transgenic Abstract: C. elegans SIR-2.1, a member of the Sir-2 family of NAD(+)-dependent protein deacetylases, has been shown to regulate nematode aging via the insulin/IGF pathway transcription factor daf-16. Treatment of C. elegans with the small molecule resveratrol, however, extends life span in a manner fully dependent upon sir-2.1, but independent of daf-16. Microarray analysis of worms treated with resveratrol demonstrates the transcriptional induction of a family of genes encoding prion-like glutamine/asparagine-rich proteins involved in endoplasmic reticulum (ER) stress response to unfolded proteins. RNA interference of abu-11, a member of this ER stress gene family, abolishes resveratrol-mediated life span extension, and overexpression of abu-11 extends the life span of transgenic animals. Furthermore, SIR-2.1 normally represses transcription of abu-11 and other ER stress gene family members, indicating that resveratrol extends life span by inhibiting sir-2.1-mediated repression of ER stress genes. Our findings demonstrate that abu-11 and other members of its ER stress gene family are positive determinants of C. elegans life span. Refer to individual Series
Project description:Fusarium graminearum and F. verticillioides are devastating cereal pathogens with very different life history and ecological characteristics. F. graminearum is homothallic, and sexual spores are an important component of its life cycle, responsible for disease initiation. F. verticilloides is heterothallic, and produces only modest numbers of fruiting bodies, which are not a significant source of inoculum. To identify corresponding differences in the transcriptional program underlying fruiting body development in the two species, comparative expression was performed, analyzing six developmental stages. To accompany the transcriptional analysis, detailed morphological characterization of F. verticillioides development was performed and compared to a previous morphological analysis of F. graminearum. Morphological development was similar between the two species, except for the observation of possible trichogynes in F. verticillioides ascogonia, which have not been previously reported for any Fusarium species. Expression of over 9000 orthologous genes were measured for the two species. Functional assignments of highly expressed orthologous genes at each time-point revealed the majority of highly expressed genes fell into the M-bM-^@M-^XM-bM-^@M-^Xunclassified proteinsM-bM-^@M-^YM-bM-^@M-^Y category, reflecting the lack of characterization of genes for sexual development in both species. Simultaneous examination of morphological development and stage-specific gene expression suggests that degeneration of the paraphyses during sexual development is an apoptotic process. Expression of mating type genes in the two species differed, possibly reflecting the divergent roles they play in sexual development. Overall, the differences in gene expression reflect the greater role of fruiting bodies in the life cycle and ecology of F. graminearum versus F. verticillioides. mRNA were sampled and compared from six time points across sexual reproduction in two Fusarium species
Project description:Abstract: C. elegans SIR-2.1, a member of the Sir-2 family of NAD(+)-dependent protein deacetylases, has been shown to regulate nematode aging via the insulin/IGF pathway transcription factor daf-16. Treatment of C. elegans with the small molecule resveratrol, however, extends life span in a manner fully dependent upon sir-2.1, but independent of daf-16. Microarray analysis of worms treated with resveratrol demonstrates the transcriptional induction of a family of genes encoding prion-like glutamine/asparagine-rich proteins involved in endoplasmic reticulum (ER) stress response to unfolded proteins. RNA interference of abu-11, a member of this ER stress gene family, abolishes resveratrol-mediated life span extension, and overexpression of abu-11 extends the life span of transgenic animals. Furthermore, SIR-2.1 normally represses transcription of abu-11 and other ER stress gene family members, indicating that resveratrol extends life span by inhibiting sir-2.1-mediated repression of ER stress genes. Our findings demonstrate that abu-11 and other members of its ER stress gene family are positive determinants of C. elegans life span. This SuperSeries is composed of the SubSeries listed below.
Project description:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for sexual spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of 2479 orthologous genes among all three species. Expression of key meiosis genes and sporulation genes, corresponded to developmental differences among these Neurospora species during sexual development. Screening N. crassa knockout crosses of genes selected for their expression differences across species, eight genes, whose functions were previously unknown, are found to be critical for the successful formation of perithecia. The absence of these genes in mutant crosses resulted in either no perithecium formation or in arrested development at an early stage. Our results provide insight into the genetic basis of Neurospora sexual reproduction, which is also of great importance with regard to other multicelluar ascomycetes, including fungal pathogens closely related to Neurospora in the Sordariomycetes, such as Fusarium spp, Magnaporthe oryzae, and Nectria haematococca mRNA were sampled and compared from eight time points across sexual reproduction in three Neurospora species