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[
International C. elegans Meeting,
1997]
In addition to the method for embryos (Tabara et al, NAR 24, 2119, 1996), we have established a protocol for in situ hybridization on whole mount larvae and adult worms. Eggs were collected from gravid worms by alkaline bleach and allowed to grow for appropriate period to obtain partially synchronized population of 4 stages, L1 to L2, L2 to L3, L3 to L4 and L4 to adult. The key point of in situ method is to satisfy both high permeability and minimal changes of morphology of the worms. Since the cuticle structure is different from stage to stage, the worm population of the 4 stages were individually fixed in separate test tubes under different conditions. Key parameters in this step were the conditions of DTT treatment and weak alkaline treatment. The fixed worms were allowed to stick to individual wells of 8 well (4 x 2) test slides in such a way that the worms of L1 to L2 were stuck on the wells of the first row, L2 to L3 worms on the second row, and so on. This arrangement enables us to observe the expression pattern throughout post-embryogenesis of two genes on a single slide. The slides were subjected to further fixation procedure and stored in ethanol until the start of hybridization. The key parameter in this step seemed the conditions of methanol treatment. Now we are applying the method to the large scale analysis of expression patterns (see the abstract by Kohara et al.).
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[
International C. elegans Meeting,
1999]
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[
Worm Breeder's Gazette,
1994]
The C.elegans cDNA project: A progress report Yuji Kohara, Tomoko Motohashi, Akiko Sugimoto, Hisako Watanabe and Hiroaki Tabara Gene Library Lab, National Institute of Genetics, Mishima 411, Japan. e-mail: ykohara@lddbj.nig.ac.jp
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[
Worm Breeder's Gazette,
1995]
The C.elegans cDNA project: A progress report Yuji Kohara, Tomoko Motohashi, Akiko Sugimoto, Hisako Watanabe and Hiroaki Tabara Gene Library Lab, National Institute of Genetics, Mishima 411, Japan e-mail: ykohara/*ddbj.nig.ac.jp Tag sequencing is now on the third set of cDNA dones. After analysis of the first set of cDNA clones (some 4,400 clones), each 10,000 clones were picked up randomly from 3 different cDNA libraries (an embryonic cDNA library and libraries of >2kb cDNA and unfractionated cDNA made from mixed stage population). The total 30,000 clones were gridded and probed with the cDNA clones belonging to the species which had been represented by more than 4 clones in the analysis of the first set. A set of some 4,800 cDNA clones (the second set) were selected out of the unhybridized clones (from rare or not analyzed cDNA species) and has been subjected to the tag sequencing. This analysis produced 3,667 clean 3'-tags which gave 1,532 more unique cDNA species (see Fig.). As the next step, the grids were further screened with the cDNA probes the groups containing more than 4 clones at the point. A set of some 4,000 cDNA clones (the third set) was selected out of the unhybridized clones and tag sequencing has been continued on this set. The current status of our progress is that we have identified 3,324 unique cDNA species out of 7,647 clones (clean 3'-tags). The unique cDNA species were assigned serial numbers from CELK00001 to CELK03324. These analyses have also detected many pairs of clones which appeared to be generated by alternative splicing. In some cases, two groups were turned out that they were derived from the same gene but had different 3'-end sequences due to alternative splicing or differential poly-A addition. We are going to make a list of such differential splicings. BLASTX search showed that 653 groups out of the 1,816 groups identified through the analysis of the second and the third sets gave significant similarities (blastx score > 100), which are listed below. (Note; "-" in the column of "Frame" means BLASTX search was made using only 3'-tag sequences so far.) Mapping and in situ analysis are in progress.
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[
Nucleic Acids Res,
1996]
We report an efficient procedure for in situ hybridization with a multi-well format on Caenorhabditis elegans embryos for large scale screening of gene expression patterns in this organism. Each hybridization well contains embryos at various stages throughout embryogenesis. The validity of the method was confirmed through results with control genes whose expression patterns have been reported;
glp-1 in very early embryos,
myo-2 in pharyngeal muscle and
unc-54 in body wall muscle. Several collagen genes and a pepsinogen gene were also examined to establish a set of lineage-specific markers. As a pilot project, we examined approximately 100 unique cDNA species classified by our cDNA project, finding that approximately 10% of the cDNA groups were expressed in specific cells and at specific stages.
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[
International C. elegans Meeting,
1995]
Previously we reported our method of in situ hybridization on whole mount embryos (WBG 13-2). The point of the method is that egg shell is removed by chitinase treatment and then the vitelline membrane is partially broken by shearing force before fixation, which takes a bit time but allow us to regulate the extent of fixation and proteinase digestion finely, leading to high signal-to-noise ratio for early embryos. The results of a model experiment using the stage-specific gene probes (
unc-54,
myo-2 ,
glp-1,
clb-2 , pepsinogen gene, etc.) verified the method. To increase the efficiency of in situ screenig, we have adapted the method to the standard 96-well format using 96-well dot-blot apparatuses. Currently, 32 different probes can be assayed on one apparatus at one time. We are applying the method onto the classified cDNA groups produced by the cDNA project in this lab (See the abstract by Kohara et al.). Thus far, very approximate estimation is that 1/20 of the cDNA groups shows specific pattern of expression during embryogenesis. We are interested very much in a clone which showed asymmetrical distribution of the mRNA in the 2-cell stage embryo since our original purpose is to search for maternal mRNA which are segregated differentially among the blastomeres. Closer examination of the clone is in progress. Another approach to identify such maternal mRNAs are also in progress using the differential display method.
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[
J Neurosci,
2003]
Thermotactic behavior in Caenorhabditis elegans is sensitive to both a worm's ambient temperature (T-amb) and its memory of the temperature of its cultivation (T-cult). The AFD neuron is part of a neural circuit that underlies thermotactic behavior. By monitoring the fluorescence of pH-sensitive green fluorescent protein localized to synaptic vesicles, we measured the rate of the synaptic release of AFD in worms cultivated at temperatures between 15 and 25degreesC, and subjected to fixed, ambient temperatures in the same range. We found that the rate of AFD synaptic release is high if either T-amb > T-cult or T-amb > T-cult, but AFD synaptic release is low if T-amb congruent to T-cult. This suggests that AFD encodes a direct comparison between T-amb and T-cult.
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[
Trends Mol Med,
2007]
Transforming growth factor beta1 (TGFbeta1), an important pleiotropic, immunoregulatory cytokine, uses distinct signaling mechanisms in lymphocytes to affect T-cell homeostasis, regulatory T (T(reg))-cell and effector-cell function and tumorigenesis. Defects in TGFbeta1 expression or its signaling in T cells correlate with the onset of several autoimmune diseases. TGFbeta1 prevents abnormal T-cell activation through the modulation of Ca(2+)-calcineurin signaling in a Caenorhabditis elegans Sma and Drosophila Mad proteins (SMAD)3 and SMAD4-independent manner; however, in T(reg) cells, its effects are mediated, at least in part, through SMAD signaling. TGFbeta1 also acts as a pro-inflammatory cytokine and induces interleukin (IL)-17-producing pathogenic T-helper cells (T(h) IL-17 cells) synergistically during an inflammatory response in which IL-6 is produced. Here, we will review TGFbeta1 and its signaling in T cells with an emphasis on the regulatory arm of immune tolerance.
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[
Genomics,
1995]
Recently, a novel family of genes with a region of homology to the mouse T locus, which is known to play a crucial, and conserved, role in vertebrate development, has been discovered. The region of homology has been named the T-box. The T-box domain of the prototypical T locus product is associated with sequence-specific DNA binding activity. In this report, we have characterized four members of the T-box gene family from the nematode Caenorhabditis elegans. All lie in close proximity to each other in the middle of chromosome III. Homology analysis among all completely sequenced T-box products indicates a larger size for the conserved T-box domain (166 to 203 residues) than previously reported. Phylogenetic analysis suggests that one C. elegans T-box gene may be a direct ortholog of the mouse Tbx2 and Drosophila omb genes. The accumulated data demonstrate the ancient nature of the T-box gene family and suggest the existence of at least three separate T-box-containing genes in a common early metazoan ancestor to nematodes and vertebrates.
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[
Glycobiology,
2006]
The common O-glycan core structure in animal glycoproteins is the core 1 disaccharide Galbeta1-3GalNAcalpha1-Ser/Thr, which is generated by addition of Gal to GalNAcalpha1-Ser/Thr by core 1 UDP-Gal:GalNAcalpha1-Ser/Thr beta1,3-galactosyltransferase (core 1 beta3-Gal-T or T-synthase, EC2.4.1.122)(2). Although O-glycans play important roles in vertebrates, much remains to be learned from model organisms such as the free-living nematode Caenorhabditis elegans, which offer many advantages in exploring O-glycan structure/function. Here we report the cloning and enzymatic characterization of T-synthase from C. elegans (Ce-T-synthase). A putative C. elegans gene for T-synthase, C38H2.2, was identified in GenBank by a BlastP search using the human T-synthase protein sequence. The full-length cDNA for Ce-T-synthase, which was generated by PCR using a C. elegans cDNA library as the template, contains 1,170 bp including the stop TAA. The cDNA encodes a protein of 389 amino acids with typical type-II membrane topology and a remarkable 42.7% identity to the human T-synthase. Ce-T-synthase has 7 Cys residues in the lumenal domain including 6 conserved Cys residues in all of the orthologs. The Ce-T-synthase has 4 potential N-glycosylation sequons, whereas the mammalian orthologs lack N-glycosylation sequons. Only one gene for Ce-T-synthase was identified in the genome-wide search and it contains 8 exons. Promoter analysis of the Ce-T-synthase using green fluorescent protein constructs show that the gene is expressed at all developmental stages and appears to be in all cells. Unexpectedly, only minimal activity was recovered in the recombinant, soluble Ce-T-synthase secreted from a wide variety of mammalian cell lines, whereas robust enzyme activity was recovered in the soluble Ce-T-synthase expressed in Hi-5 insect cells. Vertebrate T-synthase requires the molecular chaperone Cosmc, but our results show that Ce-T-synthase does not require Cosmc, and might require invertebrate-specific factors for formation of the optimally active enzyme. These results show that the Ce-T-synthase is a functional ortholog to the human T-synthase in generating core 1 O-glycans and opens new avenues to explore O-glycan function in this model organism.