Lee LW et al. (2012) J Biomed Biotechnol "The nucleolus of Caenorhabditis elegans."

Huang CR, Lee LW, Lee CC, Lo SJ

[J Biomed Biotechnol, 2012]

Nucleolar size and appearance correlate with ribosome biogenesis and cellular activity. The mechanisms underlying changes in nucleolar appearance and regulation of nucleolar size that occur during differentiation and cell cycle progression are not well understood. Caenorhabditis elegans provides a good model for studying these processes because of its small size and transparent body, well-characterized cell types and lineages, and because its cells display various sizes of nucleoli. This paper details the advantages of using C. elegans to investigate features of the nucleolus during the organism's development by following dynamic changes in fibrillarin (FIB-1) in the cells of early embryos and aged worms. This paper also illustrates the involvement of the ncl-1 gene and other possible candidate genes in nucleolar-size control. Lastly, we summarize the ribosomal proteins involved in life span and innate immunity, and those homologous genes that correspond to human disorders of ribosomopathy.

Lee LW et al. (2010) Gene "Vectors for co-expression of two genes in Caenorhabditis elegans."

Lee LW, Lo SJ, Lo HW

[Gene, 2010]

To meet the increasing need of simultaneously co-expressing two different genes in the same cell of transgenic Caenorhabditis elegans, here, we report the establishment of dicistronic vectors that contain an intercistronic region (ICR) of the C. elegans operon, CEOP5428. In these vectors, a green fluorescence protein (GFP) and a red FP (RFP) genes were placed in the first and second cistrons, respectively, which were separated by the ICR. Driven by the fibrillarin (fib-1) or myo-2 promoter, the GFP- and RFP-fusion proteins were consistently co-expressed in the entire worm cells or in the pharynx muscle cells of the transgenic worms, respectively. Our work demonstrates that ICR-containing dicistronic vectors could be developed into versatile co-expression systems in C. elegans for functional analysis of genes of interest.

Lee LW et al. (2011) Front Biosci (Elite Ed) "Hepatitis D antigens cause growth retardation and brood-size reduction in C. elegans."

Chang TY, Lee LW, Lo SJ, Lo HW

[Front Biosci (Elite Ed), 2011]

Caenorhabditis elegans is a model organism that has been used to study human bacterial and viral pathogenesis. We report here the expression of human hepatitis delta viral antigens (HDAg) in C. elegans and measure the effect on the sterility, growth, and brood size in transgenic worms. Expression of HDAg under two different promoters, fib-1 (a ubiquitous promoter) and myo-2 (a pharynx-specific promoter), was achieved in C. elegans using dicistronic or tricistronic vectors derived from the operon CEOP5428. Transgenic worms expressing HDAg ubiquitously resulted in 20% to 70% sterility while those expressing HDAg in the pharynx displayed 70% sterility. Most of worms expressing HDAg in pharynx were arrested at larvae stage 2 or 3 and displayed a 70% reduction in brood size. Domain mapping experiments suggested that the nuclear localization signal of HDAg is required for the observed effect. Heat-shock induction of HDAg expression revealed that L4 larvae were the most sensitive to brood size reduction. These studies demonstrate that C. elegans can provide an additional model for studying HDAg interactions with host targets.

Lyndal-Murphy M et al. (2010) Vet Parasitol "Reduced efficacy of macrocyclic lactone treatments in controlling gastrointestinal nematode infections of weaner dairy calves in subtropical eastern Australia."

James PJ, Pepper PM, Ehrlich WK, Rogers D, Lyndal-Murphy M

[Vet Parasitol, 2010]

Faecal Egg Count Reduction Tests (FECRTs) for macrocyclic lactone (ML) and levamisole (LEV) drenches were conducted on two dairy farms in the subtropical, summer rainfall region of eastern Australia to determine if anthelmintic failure contributed to severe gastrointestinal nematode infections observed in weaner calves. Subtropical Cooperia spp. were the dominant nematodes on both farms although significant numbers of Haemonchus placei were also present on Farm 2. On Farm 1, moxidectin pour-on (MXD) drenched at 0.5mg kg(-1) liveweight (LW) reduced the overall Cooperia burden by 82% (95% confidence limits, 37-95%) at day 7 post-drench. As worm burdens increased rapidly in younger animals in the control group (n=4), levamisole was used as a salvage drench and these calves withdrawn from the trial on animal welfare grounds after sample collection at day 7. Levamisole (LEV) dosed at 6.8mg kg(-1)LW reduced the worm burden in these calves by 100%, 7 days after drenching. On Farm 2, MXD given at 0.5mg kg(-1)LW reduced the faecal worm egg count of cooperioids at day 8 by 96% (71-99%), ivermectin oral (IVM) at 0.2mg kg(-1)LW by 1.6% (-224 to 70%) and LEV oral at 7.1mg kg(-1)LW by 100%. For H. placei the reductions were 98% (85-99.7%) for MXD, 0.7% (-226 to 70%) for IVM and 100% for LEV. This is the first report in Australia of the failure of macrocyclic lactone treatments to control subtropical Cooperia spp. and suspected failure to control H. placei in cattle.

Abate JP et al. (2009) Cell Metab "Life is short, if sweet."

Blackwell TK, Abate JP

[Cell Metab, 2009]

Insulin is essential for glucose homeostasis, but reducing its activity delays the aging process in model organisms. In this issue of Cell Metabolism, Lee et al. (2009) show how these effects of insulin signaling intersect when glucose is fed to C. elegans.

Pi H et al. (2009) Chang Gung Med J "New insights into polycistronic transcripts in eukaryotes."

Lee LW, Lo SJ, Pi H

[Chang Gung Med J, 2009]

In bacteria and archaea, many functionally related genes are organized into operons in order to be transcribed and translated simultaneously. Operons are rarely seen in eukaryotes except for the Trypanosome and nematode, in which they are first transcribed into polycistronic transcripts but then processed into individual mature mRNAs. Recently, several researchers described the findings of polycistronic transcripts also in insects, which revised the previous thoughts that polycistronic genes were absent or few in eukaryotes. Similar to prokaryotic operons, the encoded peptides or proteins are translated simultaneously from a single polycistronic mRNA, providing new insights into the evolution of polycistronic genes. More interestingly, one type of the newly identified polycistronic genes encodes biologically important peptides composed of as few as 11 amino acids. These new findings will spur scientists to identify more small peptides in genome-solved organisms, and change the definition of coding sequences in genomic annotation.

Lee C et al. (2017) Bio Protoc "Single-molecule RNA Fluorescence in situ Hybridization (smFISH) in Caenorhabditis elegans."

Sorensen EB, Lee C, Seidel HS, Lynch TR, Crittenden SL, Kimble J

[Bio Protoc, 2017]

Single-molecule RNA fluorescence <i>in situ</i> hybridization (smFISH) is a technique to visualize individual RNA molecules using multiple fluorescently-labeled oligonucleotide probes specific to the target RNA ( Raj <i>et al.</i>, 2008 ; Lee <i>et al.</i>, 2016a ). We adapted this technique to visualize RNAs in the <i>C. elegans</i> whole adult worm or its germline, which enabled simultaneous recording of nascent transcripts at active transcription sites and mature mRNAs in the cytoplasm ( Lee <i>et al.</i>, 2013 and 2016b). Here we describe each step of the smFISH procedure, reagents, and microscope settings optimized for <i>C. elegans</i> extruded gonads.

Chen YY et al. (2017) World J Virol "Expression of hepatitis B virus surface antigens induces defective gonad phenotypes in Caenorhabditis elegans."

Chen YY, Lee LW, Hong WN, Lo SJ

[World J Virol, 2017]

AIM: To test whether a simple animal, Caenorhabditis elegans (C. elegans), can be used as an alternative model to study the interaction between hepatitis B virus antigens (HBsAg) and host factors. METHODS: Three plasmids that were able to express the large, middle and small forms of HBsAgs (LHBsAg, MHBsAg, and SHBsAg, respectively) driven by a ubiquitous promoter (fib-1) and three that were able to express SHBsAg driven by different tissue-specific promoters were constructed and microinjected into worms. The brood size, egg-laying rate, and gonad development of transgenic worms were analyzed using microscopy. Levels of mRNA related to endoplasmic reticulum stress, enpl-1, hsp-4, pdi-3 and xbp-1, were determined using reverse transcription polymerase reaction (RT-PCRs) in three lines of transgenic worms and dithiothreitol (DTT)-treated wild-type worms. RESULTS: Severe defects in egg-laying, decreases in brood size, and gonad retardation were observed in transgenic worms expressing SHBsAg whereas moderate defects were observed in transgenic worms expressing LHBsAg and MHBsAg. RT-PCR analysis revealed that enpl-1, hsp-4 and pdi-3 transcripts were significantly elevated in worms expressing LHBsAg and MHBsAg and in wild-type worms pretreated with DTT. By contrast, only pdi-3 was increased in worms expressing SHBsAg. To further determine which tissue expressing SHBsAg could induce gonad retardation, we substituted the fib-1 promoter with three tissue-specific promoters (myo-2 for the pharynx, est-1 for the intestines and mec-7 for the neurons) and generated corresponding transgenic animals. Moderate defective phenotypes were observed in worms expressing SHBsAg in the pharynx and intestines but not in worms expressing SHBsAg in the neurons, suggesting that the secreted SHBsAg may trigger a cross-talk signal between the digestive track and the gonad resulting in defective phenotypes. CONCLUSION: Ectopic expression of three forms of HBsAg that causes recognizable phenotypes in transgenic worms suggests that C. elegans can be used as an alternative model for studying virus-host interactions because the resulting phenotype is easily detected through microscopy.

Dawes-Hoang RE et al. (2003) Dev Cell "Bringing classical embryology to C elegans gastrulation."

Zallen JA, Wieschaus EF, Dawes-Hoang RE

[Dev Cell, 2003]

In a recent paper, Lee and Goldstein develop an explant assay that recapitulates key aspects of gastrulation in C. elegans and permits classical embryological manipulations. The resulting detailed analysis of cell behavior will ultimately extend to broader issues, such as, whether morphogenesis can be described as the sum of single-cell events or if unique phenomena emerge at the multicellular level.

Bauer, Jack et al. (2021) MicroPubl Biol

Labb, Jean-Claude, Lacroix, La, Bauer, Jack

[MicroPubl Biol, 2021]

To perturb actomyosin function in the primordial germ line, we first monitored germ line organization in L1-stage animals bearing temperature-sensitive (ts) alleles in genes encoding actomyosin regulators and that were reported to interfere with cytokinesis during embryogenesis (Davies et al. 2014). Previous work demonstrated that the initial stages of germline expansion occur normally in cyk-4(ts) and zen-4(ts) animals raised at restrictive temperature from the L1 stage (Lee et al. 2018). We found that primordial germ line organization in cyk-1(ts), nmy-2(ts), cyk-4(ts) or zen-4(ts) L1 larvae maintained at restrictive temperature for 12h was no different than control (Figure 1A-B). Furthermore, the first primordial germ cell (PGC) division occurred normally upon feeding these animals at restrictive temperature with typical bacterial food (E. coli OP50). As noted previously (Lee et al. 2018), germ line disorganization and sterility were observed in all cases when animals reached adulthood (Figure 1B).