[
STAR Protoc,
2021]
<i>C.elegans</i> L1 larvae have two well-defined primordial germ cells embedded in a niche comprising two somatic gonad precursor cells. Thus, <i>C.elegans</i> provides an ideal model for studying intercellular signaling in response to DNA damage. However, existing staining protocols are focused on worms in later developmental stages and are not optimized for the L1 larvae. Here, we present a revised protocol for assessing the DNA damage response utilizing immunofluorescence staining specifically in <i>C.elegans</i> L1 larva. For complete details on the use and execution of this protocol, please refer to Ou etal. (2019).
[
MicroPubl Biol,
2021]
Amyotrophic lateral sclerosis (ALS) is a fatal degenerative motor neuron disease. While the mechanisms underlying motor neuron death in ALS are not well understood, mutations in over 25 genes can cause this disease (Marangi and Traynor 2015). It remains unclear which, if any, of these genes act in the same disease-associated pathway(s), or if they act in the same pathway(s) as genes associated with the related disorder, frontotemporal dementia (FTD) (Ling et al. 2013). The first ALS-causing gene to be identified was superoxide dismutase 1 (SOD1), a regulator of cytoplasmic redox homeostasis (Rosen et al. 1993). We can begin to construct a pathway for neurodegeneration through SOD1 by identifying genes whose loss of function (LOF) modifies the level of degeneration in a C. elegans SOD1 ALS model. This will contribute to our understanding of whether ALS/FTD genes act in a single or multiple pathways to cause disease.
[
RNA,
2007]
Many mRNAs in Caenorhabditis elegans are generated through a trans-splicing reaction that adds one of two classes of spliced leader RNA to an independently transcribed pre-mRNA. SL1 leaders are spliced mostly to pre-mRNAs from genes with outrons, intron-like sequences at the 5''-ends of the pre-mRNAs. In contrast, SL2 leaders are nearly exclusively trans-spliced to genes that occur downstream in polycistronic pre-mRNAs produced from operons. Operon pre-mRNA processing requires separation into individual transcripts, which is accomplished by 3''-processing of upstream genes and spliced leader trans-splicing to the downstream genes. We used a novel computational analysis, based on nonnegative matrix factorization, to identify and characterize significant differences in the cis-acting sequence elements that differentiate various types of functional site, including internal versus terminal 3''-processing sites, and SL1 versus SL2 trans-splicing sites. We describe several key elements, including the U-rich (Ur) element that couples 3''-processing with SL2 trans-splicing, and a novel outron (Ou) element that occurs upstream of SL1 trans-splicing sites. Finally, we present models of the distinct classes of trans-splicing reaction, including SL1 trans-splicing at the outron, SL2 trans-splicing in standard operons, competitive SL1-SL2 trans-splicing in operons with large intergenic separation, and SL1 trans-splicing in SL1-type operons, which have no intergenic separation.
[
PLoS One,
2010]
BACKGROUND: Proving the efficacy and corresponding mode of action of herbal supplements is a difficult challenge for evidence-based herbal therapy. A major hurdle is the complexity of herbal preparations, many of which combine multiple herbs, particularly when the combination is assumed to be vitally important to the effectiveness of the herbal therapy. This issue may be addressed through the use of contemporary methodology and validated animal models. METHODS AND PRINCIPAL FINDINGS: In this study, two commonly used traditional herbal formulas, Shi Quan Da Bu Tang (SQDB) and Huo Luo Xiao Ling Dan (HLXL) were evaluated using a survival assay and oxidative stress biomarkers in a well-established C. elegans model of aging. HLXL is an eleven herb formula modified from a top-selling traditional herbal formula for the treatment of arthritic joint pain. SQDB consists of ten herbs often used for fatigue and energy, particularly in the aged. We demonstrate here that SQDB significantly extend life span in a C. elegans model of aging. Among all individual herbs tested, two herbs Cinnamomum cassia bark (Chinese pharmaceutical name: Cinnamomi Cortex, CIN) and Panax ginseng root (Chinese pharmaceutical name: Ginseng Radix, GS) significantly extended life span in C. elegans. CIN in both SQDB and HLXL formula extended life span via modulation of multiple longevity assurance genes, including genes involved in insulin signaling and stress response pathways. All the life-span-extending herbs (SQDB, CIN and GS) also attenuated levels of H2O2 and enhanced small heat shock protein expression. Furthermore, the life span-extending herbs significantly delayed human amyloid beta (Abeta)-induced toxicity in transgenic C. elegans expressing human Abeta. CONCLUSION/SIGNIFICANCE: These results validate an invertebrate model for rapid, systematic evaluation of commonly used Chinese herbal formulations and may provide insight for designing future evidence-based herbal therapy(s).