scholarly journals A Molecular Basis for Reciprocal Regulation between Pheromones and Hormones in Response to Dietary Cues in C. elegans

2020 ◽  
Vol 21 (7) ◽  
pp. 2366
Author(s):  
Saeram Park ◽  
Jun Young Park ◽  
Young-Ki Paik
Keyword(s):  
Gene Expression ◽  
Small Molecules ◽  
Molecular Basis ◽  
Biosynthetic Gene ◽  
Reciprocal Regulation ◽  
C Elegans ◽  
Aging Period ◽  
Transcriptional Regulatory ◽  
Dietary Cues ◽  
Development And Aging

Under stressful conditions, the early larvae of C. elegans enter dauer diapause, a non-aging period, driven by the seemingly opposite influence of ascaroside pheromones (ASCRs) and steroid hormone dafachronic acids (DAs). However, the molecular basis of how these small molecules engage in competitive crosstalk in coordination with insulin/IGF-1 signaling (IIS) remains elusive. Here we report a novel transcriptional regulatory pathway that seems to operate between the ASCR and DA biosynthesis under ad libitum (AL) feeding conditions or bacterial deprivation (BD). Although expression of the ASCR and DA biosynthetic genes reciprocally inhibit each other, ironically and interestingly, such dietary cue-mediated modulation requires the presence of the competitors. Under BD, induction of ASCR biosynthetic gene expression required DA, while ASCR suppresses the expression of the DA biosynthetic gene daf-36. The negative regulation of DA by ASCR was IIS-dependent, whereas daf-36 regulation appeared to be independent of IIS. These observations suggest that the presence of ASCR determines the IIS-dependency of DA gene expression regardless of dietary conditions. Thus, our work defines a molecular basis for a novel reciprocal gene regulation of pheromones and hormones to cope with stressful conditions during development and aging.

scholarly journals Gene expression heterogeneity during brain development and aging: temporal changes and functional consequences

2019 ◽  
Author(s):  
Ulaş Işıldak ◽  
Mehmet Somel ◽  
Janet M. Thornton ◽  
Handan Melike Dönertaş
Keyword(s):  
Gene Expression ◽  
Human Brain ◽  
Meta Analysis ◽  
Brain Regions ◽  
Genetic Alterations ◽  
Individual Heterogeneity ◽  
Brain Functions ◽  
Aging Period ◽  
Gene Expression Heterogeneity ◽  
Development And Aging

AbstractCells in largely non-mitotic tissues such as the brain are prone to stochastic (epi-)genetic alterations that may cause increased variability between cells and individuals over time. Although increased inter-individual heterogeneity in gene expression was previously reported, whether this process starts during development or if it is restricted to the aging period has not yet been studied. The regulatory dynamics and functional significance of putative aging-related heterogeneity are also unknown. Here we address these by a meta-analysis of 19 transcriptome datasets from diverse human brain regions. We observed a significant increase in inter-individual heterogeneity during aging (20+ years) compared to postnatal development (0 to 20 years). Increased heterogeneity during aging was consistent among different brain regions at the gene level and associated with lifespan regulation and neuronal functions. Overall, our results show that increased expression heterogeneity is a characteristic of aging human brain, and may influence aging-related changes in brain functions.

scholarly journals Identification of piRNA binding sites reveals the Argonaute regulatory landscape of the C. elegans germline

2018 ◽  
Author(s):  
En-Zhi Shen ◽  
Hao Chen ◽  
Ahmet R. Ozturk ◽  
Shikui Tu ◽  
Masaki Shirayama ◽  
...  
Keyword(s):  
Gene Expression ◽  
Binding Sites ◽  
Small Rnas ◽  
Cross Linking ◽  
Computational Studies ◽  
Germline Gene ◽  
C Elegans ◽  
Transcriptional Regulatory ◽  
Regulatory Landscape

SUMMARYpiRNAs (Piwi-interacting small RNAs) engage Piwi Argonautes to silence transposons and promote fertility in animal germlines. Genetic and computational studies have suggested that C. elegans piRNAs tolerate mismatched pairing and in principle could target every transcript. Here we employ in vivo cross-linking to identify transcriptome-wide interactions between piRNAs and target RNAs. We show that piRNAs engage all germline mRNAs and that piRNA binding follows microRNA-like pairing rules. Targeting correlates better with binding energy than with piRNA abundance, suggesting that piRNA concentration does not limit targeting. In mRNAs silenced by piRNAs, secondary small RNAs accumulate at the center and ends of piRNA binding sites. In germline-expressed mRNAs, however, targeting by the CSR-1 Argonaute correlates with reduced piRNA binding density and suppression of piRNA-associated secondary small RNAs. Our findings reveal physiologically important and nuanced regulation of individual piRNA targets and provide evidence for a comprehensive post transcriptional regulatory step in germline gene expression.

scholarly journals The secreted endoribonuclease ENDU-2 from the soma protects germline immortality in C. elegans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjing Qi ◽  
Erika D. V. Gromoff ◽  
Fan Xu ◽  
Qian Zhao ◽  
Wei Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cell ◽  
Small Rnas ◽  
C Elegans ◽  
Cleavage Activity ◽  
Response To Temperature ◽  
Multicellular Organisms ◽  
Cell Immortality ◽  
Mature Mrnas ◽  
Endoribonuclease Activity

AbstractMulticellular organisms coordinate tissue specific responses to environmental information via both cell-autonomous and non-autonomous mechanisms. In addition to secreted ligands, recent reports implicated release of small RNAs in regulating gene expression across tissue boundaries. Here, we show that the conserved poly-U specific endoribonuclease ENDU-2 in C. elegans is secreted from the soma and taken-up by the germline to ensure germline immortality at elevated temperature. ENDU-2 binds to mature mRNAs and negatively regulates mRNA abundance both in the soma and the germline. While ENDU-2 promotes RNA decay in the soma directly via its endoribonuclease activity, ENDU-2 prevents misexpression of soma-specific genes in the germline and preserves germline immortality independent of its RNA-cleavage activity. In summary, our results suggest that the secreted RNase ENDU-2 regulates gene expression across tissue boundaries in response to temperature alterations and contributes to maintenance of stem cell immortality, probably via retaining a stem cell specific program of gene expression.

scholarly journals Identification of the Bacterial Biosynthetic Gene Clusters of the Oral Microbiome Illuminates the Unexplored Social Language of Bacteria during Health and Disease

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Gajender Aleti ◽  
Jonathon L. Baker ◽  
Xiaoyu Tang ◽  
Ruth Alvarez ◽  
Márcia Dinis ◽  
...  
Keyword(s):  
Dental Caries ◽  
Small Molecules ◽  
Gene Clusters ◽  
Signaling Molecules ◽  
Oral Bacteria ◽  
Oral Microbiome ◽  
Communication Media ◽  
Biosynthetic Gene ◽  
Colonization Resistance ◽  
Biosynthetic Gene Clusters

ABSTRACT Small molecules are the primary communication media of the microbial world. Recent bioinformatic studies, exploring the biosynthetic gene clusters (BGCs) which produce many small molecules, have highlighted the incredible biochemical potential of the signaling molecules encoded by the human microbiome. Thus far, most research efforts have focused on understanding the social language of the gut microbiome, leaving crucial signaling molecules produced by oral bacteria and their connection to health versus disease in need of investigation. In this study, a total of 4,915 BGCs were identified across 461 genomes representing a broad taxonomic diversity of oral bacteria. Sequence similarity networking provided a putative product class for more than 100 unclassified novel BGCs. The newly identified BGCs were cross-referenced against 254 metagenomes and metatranscriptomes derived from individuals either with good oral health or with dental caries or periodontitis. This analysis revealed 2,473 BGCs, which were differentially represented across the oral microbiomes associated with health versus disease. Coabundance network analysis identified numerous inverse correlations between BGCs and specific oral taxa. These correlations were present in healthy individuals but greatly reduced in individuals with dental caries, which may suggest a defect in colonization resistance. Finally, corroborating mass spectrometry identified several compounds with homology to products of the predicted BGC classes. Together, these findings greatly expand the number of known biosynthetic pathways present in the oral microbiome and provide an atlas for experimental characterization of these abundant, yet poorly understood, molecules and socio-chemical relationships, which impact the development of caries and periodontitis, two of the world’s most common chronic diseases. IMPORTANCE The healthy oral microbiome is symbiotic with the human host, importantly providing colonization resistance against potential pathogens. Dental caries and periodontitis are two of the world’s most common and costly chronic infectious diseases and are caused by a localized dysbiosis of the oral microbiome. Bacterially produced small molecules, often encoded by BGCs, are the primary communication media of bacterial communities and play a crucial, yet largely unknown, role in the transition from health to dysbiosis. This study provides a comprehensive mapping of the BGC repertoire of the human oral microbiome and identifies major differences in health compared to disease. Furthermore, BGC representation and expression is linked to the abundance of particular oral bacterial taxa in health versus dental caries and periodontitis. Overall, this study provides a significant insight into the chemical communication network of the healthy oral microbiome and how it devolves in the case of two prominent diseases.

scholarly journals A rapid and massive gene expression shift marking adolescent transition in C. elegans

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
L. Basten Snoek ◽  
Mark G. Sterken ◽  
Rita J. M. Volkers ◽  
Mirre Klatter ◽  
Kobus J. Bosman ◽  
...  
Keyword(s):  
Gene Expression ◽  
C Elegans ◽  
Adolescent Transition

scholarly journals Epigenetic events in medulloblastoma development

2005 ◽  
Vol 19 (5) ◽  
pp. 1-13 ◽  
Author(s):  
Janet C. Lindsey ◽  
Jennifer A. Anderton ◽  
Meryl E. Lusher ◽  
Steven C. Clifford
Keyword(s):  
Gene Expression ◽  
Tumor Suppressor Genes ◽  
Molecular Basis ◽  
Gene Disruption ◽  
Functional Role ◽  
Promoter Hypermethylation ◽  
Therapeutic Approaches ◽  
Primary Tumors ◽  
Molecular Events ◽  
Epigenetic Events

Over the last decade, the analysis of genetic defects in primary tumors has been central to the identification of molecular events and biological pathways involved in the pathogenesis of medulloblastoma, the most common malignant brain tumor of childhood. Despite this, understanding of the molecular basis of the majority of cases remains poor. In recent years, the emerging field of epigenetics, which describes heritable alterations in gene expression that occur in the absence of DNA sequence changes, has forced a revision of the understanding of the mechanisms of gene disruption in cancer. Accumulating evidence indicates a significant involvement for epigenetic events in medulloblastoma development. Recent studies have identified a series of candidate tumor suppressor genes (for example, RASSF1A, CASP8, and HIC1) that are each specifically epigenetically inactivated in a large proportion (> 30%) of medulloblastomas by promoter hypermethylation, leading to the silencing of their gene expression. These findings shed new light on medulloblastoma and offer great potential for an improved understanding of its molecular pathology. The authors review the current understanding of epigenetic events in cancer and their contribution to medulloblastoma development. Their nature, origins, and functional role(s) in tumorigenesis are considered, and the authors assess the potential utility of these events as a basis for novel diagnostic and therapeutic approaches.

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