Browsing by keyword "*Genome, Helminth"
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Genome-scale spatiotemporal analysis of Caenorhabditis elegans microRNA promoter activityThe Caenorhabditis elegans genome encodes more than 100 microRNAs (miRNAs). Genetic analyses of miRNA deletion mutants have only provided limited insights into miRNA function. To gain insight into the function of miRNAs, it is important to determine their spatiotemporal expression pattern. Here, we use miRNA promoters driving the expression of GFP as a proxy for miRNA expression. We describe a set of 73 transgenic C. elegans strains, each expressing GFP under the control of a miRNA promoter. Together, these promoters control the expression of 89 miRNAs (66% of all predicted miRNAs). We find that miRNA promoters drive GFP expression in a variety of tissues and that, overall, their activity is similar to that of protein-coding gene promoters. However, miRNAs are expressed later in development, which is consistent with functions after initial body-plan specification. We find that miRNA members belonging to families are more likely to be expressed in overlapping tissues than miRNAs that do not belong to the same family, and provide evidence that intronic miRNAs may be controlled by their own, rather than a host gene promoter. Finally, our data suggest that post-transcriptional mechanisms contribute to differential miRNA expression. The data and strains described here will provide a valuable guide and resource for the functional analysis of C. elegans miRNAs.
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The genome and transcriptome of the zoonotic hookworm Ancylostoma ceylanicum identify infection-specific gene familiesHookworms infect over 400 million people, stunting and impoverishing them. Sequencing hookworm genomes and finding which genes they express during infection should help in devising new drugs or vaccines against hookworms. Unlike other hookworms, Ancylostoma ceylanicum infects both humans and other mammals, providing a laboratory model for hookworm disease. We determined an A. ceylanicum genome sequence of 313 Mb, with transcriptomic data throughout infection showing expression of 30,738 genes. Approximately 900 genes were upregulated during early infection in vivo, including ASPRs, a cryptic subfamily of activation-associated secreted proteins (ASPs). Genes downregulated during early infection included ion channels and G protein-coupled receptors; this downregulation was observed in both parasitic and free-living nematodes. Later, at the onset of heavy blood feeding, C-lectin genes were upregulated along with genes for secreted clade V proteins (SCVPs), encoding a previously undescribed protein family. These findings provide new drug and vaccine targets and should help elucidate hookworm pathogenesis.
