最新發表
[ 張雯 博士 ] - August, 2008, 2008Vaccinia viral protein WR53.5/F14.5 is a new component of intracellular mature virus and is important for calcium-independent cell adhesion and vaccinia virus virulence in mice
The vaccinia virus WR53.5L/F14.5L gene encodes a small conserved protein that was not detected previously. However, additional proteomic analyses of different vaccinia virus isolates and strains revealed that the WR53.5 protein was incorporated into intracellular mature virus (IMV). The WR53.5 protein contains a putative N-terminal transmembrane region and a short C-terminal region. Protease digestion removed the C-terminus of WR53.5 protein from IMV particles, suggesting a similar topology to that of the IMV type II transmembrane protein. We generated a recombinant vaccinia virus, vi53.5L, that expressed WR53.5 protein under IPTG regulation, and found that the vaccinia virus life cycle proceeded normally with or without IPTG, suggesting that WR53.5 protein is not essential for vaccinia virus growth in cell cultures. Interestingly, the C-terminal region of WR53.5 protein was exposed on the cell surface of infected cells and mediated calcium-independent cell adhesion. Finally, viruses with inactivated WR53.5L gene expression exhibited reduced virulence in mice when inoculated intranasally, demonstrating that WR53.5 protein was required for virus virulence in vivo. In summary, we identified a new vaccinia IMV envelope protein WR53.5 that mediates cell adhesion and is important for virus virulence in vivo. J. Virol. doi:10.1128/JVI.00816-08 Read more...
[ 孫以瀚 博士 ] - July, 2008Temporal switching of regulation and function of eye gone (eyg) in Drosophila eye development.
The Pax gene eyg is important for Drosophila eye development. eyg expression in the visual system changes dynamically during development. In this study, we found that the transcriptional regulation of eyg can be separated into four distinct temporal phases (E, L1, L2, and L3) and each is regulated by distinct cis regulatory elements. Utilizing these enhancers for temporal and spatially specific manipulations, we addressed the regulation and function of eyg at different developmental stages. We found that Notch signaling is required and sufficient for eyg expression and this activity is restricted only to the L2 stage. We further showed that the function of eyg in eye development is required only at the second instar larval stage, while its function for head and antenna development can be provided at any time during embryo and larval development. Thus there is a temporal switch of the regulatory mechanism and function of eyg. We propose that eyg expression at L2 is induced and maintained by N signaling, and is turned off at L3 by a negative feedback loop involving the morphogenetic furrow. Dev Biol. 2008 Jul 4.
[ Dr. Soo-Chen Cheng ] - June, 2008Both catalytic steps of nuclear pre-mRNA splicing are reversible
Nuclear pre–messenger RNA (pre-mRNA) splicing is an essential processing step for the production of mature mRNAs from most eukaryotic genes. Splicing is catalyzed by a large ribonucleoprotein complex, the spliceosome, which is composed of five small nuclear RNAs and more than 100 protein factors. Despite the complexity of the spliceosome, the chemistry of the splicing reaction is simple, consisting of two consecutive transesterification reactions. The presence of introns in spliceosomal RNAs of certain fungi has suggested that splicing may be reversible; however, this has never been demonstrated experimentally. By using affinity-purified spliceosomes, we have shown that both catalytic steps of splicing can be efficiently reversed under appropriate conditions. These results provide considerable insight into the catalytic flexibility of the spliceosome. Science 320, 1782-1784. Read more...
[ 薛一蘋 博士 ] - July, 2008SUMOylation of the MAGUK protein CASK regulates dendritic spinogenesis
Membrane-associated guanylate kinase (MAGUK) proteins interact with several synaptogenesis-triggering adhesion molecules. However, direct evidence for the involvement of MAGUK proteins in synapse formation is lacking. In this study, we investigate the function of calcium/calmodulin-dependent serine protein kinase (CASK), a MAGUK protein, in dendritic spine formation by RNA interference. Knockdown of CASK in cultured hippocampal neurons reduces spine density and shrinks dendritic spines. Experiments using only the CASK PDZ domain or a mutant lacking the protein 4.1-binding site indicate an involvement of CASK in linking transmembrane adhesion molecules and the actin cytoskeleton. Moreover, we find that CASK is SUMOylated. Conjugation of SUMO1 to CASK reduces the interaction between CASK and protein 4.1. Overexpression of a CASK-SUMO1 fusion construct, which mimicks CASK SUMOylation, impairs spine formation. Our study suggests that CASK contributes to spinogenesis and that this is controlled by SUMOylation. Journal of Cell Biology doi:10.1083/jcb.200712094 Read more...
[ 張雯 博士 ] - June, 2008A novel cellular protein, VPEF, facilitates vaccinia virus penetration into HeLa cells through fluid phase endocytosis
Vaccinia virus is a large DNA virus that infects many cell cultures in vitro and animal species in vivo. Although it has been used widely as a vaccine, its cell entry pathway remains unclear. In this study, we showed that vaccinia intracellular mature virions bound to the filopodia of HeLa cells and moved towards the cell body and entered the cell through an fluid phase endocytic route that required a dynamin- but not a clathrin- or caveolae-mediated pathway. Moreover, virus penetration required a novel cellular protein, vaccinia penetration factor (VPEF). J. Virol. published 11 June 2008, 10.1128/JVI.00894-08. Read more...
[
沈哲鯤 博士 ] - May, 2008TDP -43, the signature protein of FTLD-U, is a neuronal activity-responsive factor
TDP-43 is a multifunctional RNA-binding protein that we have been studying since 2000. In 2006, it was discovered by others to be a pathological signature protein of several neurodegenerative diseases including the amyotrophic lateral sclerosis (ALS). This paper presents the first evidence that TDP-43 very likely functions in the regulation of neuronal activities.. J. Neurochem., 105 (3),797-806. Read more...
[
鍾邦柱 博士 ] - April, 2008Mutation of mouse Cyp11a1 promoter caused tissue-specific reduction of gene expression and blunted stress response without affecting reproduction
CYP11A1 is an enzyme catalyzing steroid synthesis. To understand the regulation of steroid secretion, Bon-chu Chung’s lab mutated the promoter of the mouse Cyp11a1 gene. The resulting mutant mice express less Cyp11a1, secrete insufficient glucocorticoid, and had reduced stress response. This study creates a mouse model for the study of stress response. Mol. Endocrinol. 22, 915-923 (2008). Read more...
[ 李秀敏 博士 ] - March, 2008Arabidopsis Stromal 70-kD Heat Shock Proteins Are Essential for Plant Development and Important for Thermotolerance of Germinating Seeds
Targeting and biological functions of two plastid stromal Hsp70s, cpHsc70-1 and cpHsc70-2, were examined. Our results indicate that stromal Hsp70s are essential for plant development, because double mutation was lethal. After heat shock treatment of germinating seeds, root growth from 
cphsc70-1 seeds was further impaired, suggesting that cpHsc70-1 is important for thermotolerance of germinating seeds.
Plant Physiology 146:1231-1241 (2008). Read more..
[ Dr. Su-May Yu ]
Fish eye in rice seeds? -- Global functional analyses of rice promoters by genomics approaches
Using the promoter-trap lines that are part of the Taiwan Rice Insertional Mutant (TRIM) library (Plant Mol Biol 2007 63:351-64), Su-May Yu leading a group that includes Tuan-Hua David Ho, Swee-Suak Ko, Chii-Gong Tong, and Yue-Ie Hsing from the Institute of Plant and Microbial Biology have developed a systematic way to conduct a genome-wide search for tissue-specific promoters (Plant Molecular Biology 65:417-425). They systematically performed GUS activity screens of the rice mutant library for genes/promoters constitutively, differentially, or specifically active in vegetative and reproductive tissues. In addition, by integrating the promoter trap data with microarray data from stress- and ABA-treated plants, they were able to identify promoters induced by stress and/or ABA in a tissue specific manner. Such promoters are potentially useful in construction of plants with improved stress tolerance.
IL-15 does not affect IEL development in the thymus but regulates homeostasis of putative precursor and mature CD8αα+ IELs in the intestine
Mice devoid of the IL-15 system lose over 90% of CD8αα+ TCRαβ (αβ) and γδ intestinal intraepithelial lymphocytes (iIEL). It remains unclear when and how the IL-15 system affects CD8αα+ iIEL through their development. This study found that IL-15Rα is dispensable for the thymic stage of CD8αα+αβ and γδ iIEL development, but is required for the maintenance and/or differentiation of the putative lineage marker negative precursors in the intestinal epithelium, especially for the most mature CD8 single positive subset. Moreover, the IL-15 system directly supports the survival of mature CD8αα+ iIEL in vivo.. The Journal of Immunology 180: 3757-3765 (2008). Read more..
研究領域