Environmental cues transduced by an endocrine network converge on Caenorhabditis elegans nuclear receptor DAF-12 to mediate arrest at dauer diapause or continuous larval development. In adults, DAF-12 selects long-lived or short-lived modes. How these organismal choices are molecularly specified is unknown. Here we show that coregulator DIN-1 and DAF-12 physically and genetically interact to instruct organismal fates. Homologous to human corepressor SHARP, DIN-1 comes in long (L) and short (S) isoforms, which are nuclear localized but have distinct functions. DIN-1L has embryonic and larval developmental roles. DIN-1S, along with DAF-12, regulates lipid metabolism, larval stage-specific programs, diapause, and longevity. Epistasis experiments reveal that din-1S acts in the dauer pathways downstream of lipophilic hormone, insulin/IGF, and TGF␤ signaling, the same point as daf-12. We propose that the DIN-1S/DAF-12 complex serves as a molecular switch that implements slow life history alternatives in response to diminished hormonal signals.[Keywords: Nuclear receptor; coregulator; aging; dauer; heterochrony] Supplemental material is available at http://www.genesdev.org.

During metazoan development, cells acquire both positional and temporal identities. The Caenorhabditis elegans heterochronic loci are global regulators of larval temporal fates. Most encode conserved transcriptional and translational factors, which affect stage-appropriate programs in various tissues. Here, we describe dre-1, a heterochronic gene, whose mutant phenotypes include precocious terminal differentiation of epidermal stem cells and altered temporal patterning of gonadal outgrowth. Genetic interactions with other heterochronic loci place dre-1 in the larval-to-adult switch. dre-1 encodes a highly conserved F box protein, suggesting a role in an SCF ubiquitin ligase complex. Accordingly, RNAi knockdown of the C. elegans SKP1-like homolog SKR-1, the cullin CUL-1, and ring finger RBX homologs yielded similar heterochronic phenotypes. DRE-1 and SKR-1 form a complex, as do the human orthologs, hFBXO11 and SKP1, revealing a phyletically ancient interaction. The identification of core components involved in SCF-mediated modification and/or proteolysis suggests an important level of regulation in the heterochronic hierarchy.

Francisella (F.) tularensis is a highly virulent, Gram-negative bacterial pathogen and the causative agent of the zoonotic disease tularemia. Here, we generated, analyzed and characterized a high quality circular genome sequence of the F. tularensis subsp. holarctica strain 12T0050 that caused fatal tularemia in a hare. Besides the genomic structure, we focused on the analysis of oriC, unique to the Francisella genus and regulating replication in and outside hosts and the first report on genomic DNA methylation of a Francisella strain. The high quality genome was used to establish and evaluate a diagnostic whole genome sequencing pipeline. A genotyping strategy for F. tularensis was developed using various bioinformatics tools for genotyping. Additionally, whole genome sequences of F. tularensis subsp. holarctica isolates isolated in the years 2008–2015 in Germany were generated. A phylogenetic analysis allowed to determine the genetic relatedness of these isolates and confirmed the highly conserved nature of F. tularensis subsp. holarctica.

Investigations of cellular processes initiated by volatile organic compounds (VOCs) are limited when modelling realistic long-term exposure scenarios at low concentrations. Exposure to indoor VOCs is associated with a range of adverse effects, but data on molecular changes at regulatory threshold limits are lacking. Activity analysis of VOC in vitro can be a valuable complement to inhalation toxicological evaluations. We developed an exposure platform that generates a stable VOC atmosphere and allows the exposure of cells for longer periods. Using formaldehyde as a model analyte, air-liquid interface cultured A549 lung epithelial cells were exposed to critical concentrations of 0.1 and 0.5 ppm for 3 days. Owing to the lack of known exposure biomarkers, we applied a genome-wide transcriptional analysis to investigate cellular responses at these sublethal concentrations. We demonstrate a minor overlap of differentially expressed transcripts for both treatment concentrations, which can be further analyzed for their use as exposure biomarkers. Moreover, distinct expression patterns emerge for 0.1 and 0.5 ppm formaldehyde exposure, which is reflected in significant enrichment of distinct biological processes. More specifically, metabolism of specific compound classes, lipid biosynthesis and lung-associated functions are affected by lower exposure levels and processes affecting proliferation and apoptosis dominate the higher exposure levels.

Zoonotic pathogens that can be transmitted via food to humans have a high potential for large-scale emergencies, comprising severe effects on public health, critical infrastructures, and the economy. In this context, the development of laboratory methods to rapidly detect zoonotic bacteria in the food supply chain, including highresolution mass spectrometry proteotyping are needed. In this work, an optimized sample preparation method for liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteome profiling was established for Francisella isolates, and a cluster analysis, as well as a phylogenetic tree, was generated to shed light on evolutionary relationships. Furthermore, this method was applied to tissues of infected hare carcasses from Germany. Even though the non-informative data outnumbered by a manifold the information of the zoonotic pathogen in the resulting proteome profiles, the standardized evaluation of MS data within an established automated analysis pipeline identified Francisella (F.) tularensis and, thus, could be, in principle, an applicable method to monitor food supply chains.