Project description:microRNAs (miRNAs) constitute a class of small non-coding RNAs (~22nt). They are thought to be generally stable with half-lives of many hours or even days. However, several miRNAs have been reported to decay rapidly in specific situations. In order to examine miRNA stability on a global scale, we quantify relative decay rates of miRNA in first larval stage C. elegans worms that are treated with a transcription inhibitor alpha-amanitin by deep sequencing. Several miRNAs including members of the miR-35 and miR-51 families exhibit accelerated decay. Moreover, biogenesis of miRNAs involves generation of a miRNA duplex intermediate consisting of the miRNA guide strand (miR) and the miRNA passenger strand (miR*). miR and miR* names were originally assigned based on the relative abundance of each strand, with the less abundant strand presumed to be inactive, and thus the miR*. However, subsequent research showed that at least individual miR*s can have biological activity. Our sequencing data reveal that miR*s, operationally defined on the basis of their relative abundance at time point t=1h, are substantially less stable than miRs. This would appear to support the notion that miR*s mainly constitute processing byproducts rather than a less abundant class of functional miRNAs. Examination of microRNA decay rates in the first larval stage C. elegans worms.
Project description:The nematode Caenorhabditis elegans (C. elegans) is often used as a model organism to study cell and developmental biology. Quantitative mass spectrometry has only recently been performed in C. elegans and, so far, most studies have been done on adult worm samples. Here we use quantitative mass spectrometry to characterise protein level changes across the four larval developmental stages (L1-L4) of C. elegans, in biological triplicate. In total, we identify 4,130 proteins and quantify 1,541 proteins that were identified across all four stages in all three biological repeats with at least 2 unique peptides per protein. Using hierarchical clustering and functional ontological analyses, we identify 21 protein groups containing proteins with similar protein profiles across the four stages, and highlight the most overrepresented biological functions in each of these protein clusters. In addition, we use the dataset to identify putative larval stage specific proteins in each individual developmental stage, as well as in the early and late developmental stages. In summary, this dataset provides a system-wide analysis of protein level changes across the four C. elegans larval developmental stages, which serves as a useful resource for the worm development research community.
Project description:Transcriptional profiling of N2 (WT) and miR-85(m4117) Caenorhabditis elegans at larval stage 4 (L4) compared at either control temperature (20°C) or after 3hr HS (35°C).
Project description:In this study, we exposed Caenorhabditis elegans wild types N2 to water collected from six sources in the Dutch village Sneek. The sources were: wastewater from a hospital, a community (80 households), a nursing home, influent into the local municipal wastewater treatment plant, effluent of the wastewater treatment plant, and surface water samples. The goal of the experiment was to determine if C. elegans can be used to identify pollutants in the water by transcriptional profiling. Age synchronized worms at developmental L4 larval stage were exposed to treatment for 24 hours. After flash freezing the samples, RNA was isolated, labeled and hybridized on oligo microarray (Agilent) slides.