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Genome Res,
2021]
Recently developed single-cell technologies allow researchers to characterize cell states at ever greater resolution and scale. <i>C. elegans</i> is a particularly tractable system for studying development, and recent single-cell RNA-seq studies characterized the gene expression patterns for nearly every cell type in the embryo and at the second larval stage (L2). Gene expression patterns give insight about gene function and into the biochemical state of different cell types; recent advances in other single-cell genomics technologies can now also characterize the regulatory context of the genome that gives rise to these gene expression levels at a single-cell resolution. To explore the regulatory DNA of individual cell types in <i>C. elegans</i>, we collected single-cell chromatin accessibility data using the sci-ATAC-seq assay in L2 larvae to match the available single-cell RNA-seq data set. Using a novel implementation of the latent Dirichlet allocation algorithm, we identify 37 clusters of cells that correspond to different cell types in the worm, providing new maps of putative cell type-specific gene regulatory sites, with promise for better understanding of cellular differentiation and gene regulation.
Cortez, Angel, Hastie, Eric, Attix, Haley, Zarilla, Kathy, Cho, Martin, George, Alex, Panchal, Henali
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MicroPubl Biol,
2021]
Research experiences in community college lead to increased retention in science, technology, engineering, and mathematics (STEM) (Nerio et al., 2019). This two week undergraduate research experience (URE) was designed to enhance laboratory skills in students with limited prior exposure, introduce developmental biology and genetics in a model organism system (C. elegans), and encourage participation in generation of data for a micropublication. The University of North Carolina at Chapel Hill and Durham Technical Community College partnered to host the URE for two weeks, for two hours, 4 days a week to limit lab time for students who work full time jobs. Here, we report our findings comparing early developmental cell division of wild type N2 embryos and a wild caught strain that was obtained from soil outside of Loeb Hall in Woods Hole, MA in 2017. The strain, originally called WH strain, was grown on OP50 and survived, suggesting it is a bacteriovore. The WH nematode lays embryos at the one cell stage, making early divisions observable without the dissection or bleaching required for the N2 strain. Students used primers to amplify the 18S ribosomal subunit geneused in phylogenetic analysis of taxafrom extracted genomic DNA and sent the product for sequencing (Floyd et al., 2005). The hairpin 17 region was selected to display a comparison because of high conservation (Nyaku et al., 2013). BLAST results for the N2 strain matched N2 and results for the wild caught WH strain matched with the nematode strain Acrobeloides sp. LKC 27 (a match of 99.7% and E value of 0), available from the Caenorhabditis Genetics Center. LKC 27 was isolated from a western corn rootworm from a Brookings, SD insectary in 2003 (personal communication with Dr. Lynn Carta, USDA-ARS). Students concluded that additional loci need to be examined to determine the relationship of the WH strain to LKC 27.