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991.
RPB1 and RPB2, which encode the largest and second largest subunits of RNA polymerase II, respectively, are essential single copy genes in fungi, animals and most plants. Two paralogs of the RPB2 gene have been found in some groups of angioperms [Oxelman, B., Yoshikawa, N., McConaughy, B.L., Luo, J., Denton, A.L., Hall, B.D., 2004. RPB2 gene phylogeny in flowering plants, with particular emphasis on asterids. Mol. Phylogenet. Evol. 32, 462-479]. Here, we report the results of experiments designed to identify the evolutionary origin of the RPB2 duplicate copies. Through careful sampling and phylogenetic analysis, we were able to construct the RPB2 gene tree in angiosperms and infer the phylogenetic positions of the gene duplication and gene loss events that occurred. Our study shows that an RPB2 gene duplication occurred early in core eudicot evolution, at or near the time of the Buxaceae/Trochodendraceae divergence. Subsequently, multiple gene duplication and paralog sorting events happened independently in different core eudicot taxa. Differential expression of the two RPB2 gene paralogs may explain the preservation of both paralogs in the asterids. One gene (RPB2-i) accounts for most of the RPB2 mRNA made in the flower organs while the other gene (RPB2-d) is predominantly used in the vegetative tissues. We also found two paralogs of the RPB1 gene in some core eudicot species. The RPB1 gene duplication occurred before core eudicot divergence, around the time of RPB2 gene duplication. Several independent RPB1 paralog sorting events happened in different core eudicot taxa; their occurrence was independent of the RPB2 paralog sorting events. Our results suggest that a polyploidization event happened at or near the time of the Buxaceae/Trochodendraceae divergence. We propose that this polyploidization and the partial diploidization processes thereafter may have been the driving force of core eudicot radiation. 相似文献
992.
Trivedi CM Luo Y Yin Z Zhang M Zhu W Wang T Floss T Goettlicher M Noppinger PR Wurst W Ferrari VA Abrams CS Gruber PJ Epstein JA 《Nature medicine》2007,13(3):324-331
In the adult heart, a variety of stresses induce re-expression of a fetal gene program in association with myocyte hypertrophy and heart failure. Here we show that histone deacetylase-2 (Hdac2) regulates expression of many fetal cardiac isoforms. Hdac2 deficiency or chemical histone deacetylase (HDAC) inhibition prevented the re-expression of fetal genes and attenuated cardiac hypertrophy in hearts exposed to hypertrophic stimuli. Resistance to hypertrophy was associated with increased expression of the gene encoding inositol polyphosphate-5-phosphatase f (Inpp5f) resulting in constitutive activation of glycogen synthase kinase 3beta (Gsk3beta) via inactivation of thymoma viral proto-oncogene (Akt) and 3-phosphoinositide-dependent protein kinase-1 (Pdk1). In contrast, Hdac2 transgenic mice had augmented hypertrophy associated with inactivated Gsk3beta. Chemical inhibition of activated Gsk3beta allowed Hdac2-deficient adults to become sensitive to hypertrophic stimulation. These results suggest that Hdac2 is an important molecular target of HDAC inhibitors in the heart and that Hdac2 and Gsk3beta are components of a regulatory pathway providing an attractive therapeutic target for the treatment of cardiac hypertrophy and heart failure. 相似文献
993.
Constitutive expression of human angiostatin in <Emphasis Type="Italic">Pichia pastoris</Emphasis> by high-density cell culture 总被引:1,自引:0,他引:1
Zhang AL Zhang TY Luo JX Chen SC Guan WJ Fu CY Peng SQ Li HL 《Journal of industrial microbiology & biotechnology》2007,34(2):117-122
A high-density cell culture method to produce human angiostatin has been successfully established by constitutive expression
of the protein in Pichia pastoris. The fermentation was carried out in a 20 l bioreactor with a 10 l working volume, using a high-density cell culture method
by continuously feeding with 50% glycerol−0.8% PTM4 to the growing culture for 60 h at 30°C. Dissolved oxygen level was maintained
at 25–30% and pH was controlled at 5 by the addition of 7 M NH4OH. Angiostatin was constitutively expressed during the fermentation by linking its expression to the P. pastoris constitutive GAP promoter (pGAP). But after 36 h of fermentation, the peak biomass growth was 305 as measured by absorption
of 600 nm, while the peak angiostatin expression was 176 mg/l. Similar to the product expressed from inducible system [24], angiostatin produced from constitutive system also inhibited the angiogenesis on the CAM and suppressed the growth of B16
melanoma in C57BL/6J mouse. The above results suggest that GAP promoter is more efficient than AOX1 promoter for the expression
of angiostatin in P. pastoris by shake flask culture or high-density cell fermentation and is likely to be an alternative to AOX1 promoter in large-scale
expression of angiostatin and other heterologous proteins.
Supported by the Natural Science Foundation of China (39670013) and “225” Science and Technology Program of Guangzhou Municipal
Government of China (99-Z-004-001). 相似文献
994.
Structured to reduce the mitogenicity of anti-CD3 antibody based on computer-guided molecular design
Lv M Li Y Yu M Sun Y Lin Z Qiao C Luo Q Gu X Huang Y Feng J Shen B 《The international journal of biochemistry & cell biology》2007,39(6):1142-1155
The mouse anti-human CD3 monoclonal antibody such as OKT3 is a potent immunosuppressive agent used in clinical transplantation to manipulate T-cell functions and prevent acute allograft rejection. However, the broad use of anti-CD3 antibody in clinical treatment was severely limited by the side effects of human anti-mouse antibody response and cytokine release syndrome. In this study, on the basis of a murine anti-human CD3 antibody yCD3 obtained in our previous work, a novel engineered anti-human CD3 antibody fragment (i.e. V(H)-Linker-V(L)-Hinge-CH(3)) was constructed with computer-guided molecular design method to avoid the clinical side effects. According to the distance geometry and intra-molecular interaction, the hinge region was re-designed and different from the parental hinge region in human IgG1. With the novel hinge region, the cysteine residues in hinge were exposure and prone to form the disulfide bond. Therefore, a novel bivalent antibody fragment named as mini-yCD3 was obtained. Mini-yCD3 displayed similar antigen-binding affinity and specificity to yCD3. Importantly, mini-yCD3 was shown to be much less potent in the induction of T-cell proliferation, cytokine release (interferon-gamma and interleukin-2) and early activation marker expression on the cell surface (CD69 and CD25) than parental yCD3. Furthermore, mini-yCD3 was effective in modulating T-cell receptor/CD3 and inhibiting mixed lymphocyte reaction with similarity as yCD3. In conclusion, the constructed mini-yCD3 was much less mitogenic to T cells but retained potent immunosuppression, suggesting it might be an alternative to yCD3 as an immunosuppressive drug with less immunogenicity and toxicity for clinical application. 相似文献
995.
Bacillus cereus is believed to be a soil bacterium, but studied solely in laboratory culture media. The aim of this study was to assess the physiology of B. cereus growing on soil organic matter by a proteomic approach. Cells were cultured to mid-exponential phase in soil extracted solubilized organic matter (SESOM), which mimics the nutrient composition of soil, and in Luria-Bertani broth as control. Silver staining of the two-dimensional gels revealed 234 proteins spots up-regulated when cells were growing in SESOM, with 201 protein spots down-regulated. Forty-three of these differentially expressed proteins were detected by Colloidal Coomassie staining and identified by matrix assisted laser desorption ionization-time of flight MS of tryptic digests. These differentially expressed proteins covered a range of functions, primarily amino acid, lipid, carbohydrate and nucleic acid metabolism. These results suggested growth on soil-associated carbohydrates, fatty acids and/or amino acids, concomitant with shifts in cellular structure. 相似文献
996.
997.
Summary. Taurine is found in bone tissue, but its function in skeletal tissue is not fully understood. The present study was undertaken
to investigate regulation of gene expression of connective tissue growth factor (CTGF), and the roles of mitogen-activated
protein kinases (MAPKs) in murine osteoblast MC3T3-E1 cells treated with taurine. Western blot analysis showed taurine stimulated
CTGF protein secretion in a dose- and time-dependent manner. Taurine induced activation of extracellular signal-regulated
kinase (ERK), but not p38 and c-jun N-terminal Kinase (JNK), in osteoblasts. Furthermore, pretreatment of osteoblasts with the ERK inhibitor PD98059 abolished
the taurine-induced CTGF production. These data indicate that taurine induces CTGF secretion in MC3T3-E1 cells mediated by
the ERK pathway, and suggest that osteoblasts are direct targets of taurine. 相似文献
998.
Webber Liao Andrew Collins Matthew Hobbs Mehar S. Khatkar Junhong Luo Frank W. Nicholas 《Mammalian genome》2007,18(5):287-299
We have adapted the Location Database (LDB) map-integration strategy of Morton et al. [Ann Hum Genet 56:223–232] (1992) as
above to create an integrated map for each of several species for which fully annotated genome sequences are not yet available
(sheep, cattle, pig, wallaby), using all types of partial maps for that species, including cytogenetic, linkage, somatic-cell
hybrid, and radiation hybrid maps. An integrated map provides not only predictions of the kilobase location of every locus,
but also predicts locations (in cM) and cytogenetic band locations for every locus. In this way a comprehensive linkage map
and a comprehensive cytogenetic map are created, including all loci, irrespective of whether they have ever been linkage mapped
or physically mapped, respectively. High-resolution physical maps from annotated sequenced species have also been placed alongside
the integrated maps. This has created a powerful tool for comparative genomics. The LDB map-integration strategy has been
extended to make use of zoo-FISH comparative information. It has also been extended to enable the creation of a “virtual”
map for each species not yet sequenced by using mapping data from fully sequenced species. All of the partial maps, together
with the integrated map, for each species have been placed in a database called Comparative Location Database (CompLDB), which
is available for querying, browsing, or download in tabular form at .
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
999.
1000.
Jiong Yang Shunkai Yang Ya-Li Yang Hu Zheng Lingling Weng Luo Liu 《Journal of Molecular Catalysis .B, Enzymatic》2007,47(3-4):155-158
A novel synthetic route to rimexolone, a corticosteroid for treatment of ocular inflammation without significant elevation of intraocular pressure, was described. An investigation has been undertaken of the microbial transformation of 16α,17α-dimethyl-17β-(l-oxopropyl)androsta-l,4-dien-3-one by microorganisms known to hydroxylate conventional steroids, using Curvularia lunata AS 3.4381 gave rimexolone, the product of 11β-hydroxylation, respectively. The target compound was characterized with reference substance rimexolone by TLC, HPLC, elemental analysis, MS, IR, and NMR. 相似文献