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71.
Long-distance signals generated in shoots are thought to be associated with the regulation of iron uptake from roots; however,
the signaling mechanism is still unknown. To elucidate whether the signal regulates iron uptake genes in roots positively
or negatively, we analyzed the expressions of two representative iron uptake genes: NtIRT1 and NtFRO1 in tobacco (Nicotiana tabacum L.) roots, after shoots were manipulated in vitro. When iron-deficient leaves were treated with Fe(II)-EDTA, the expressions
of both genes were significantly reduced; nevertheless iron concentration in the roots maintained a similar level to that
in roots grown under iron-deficient conditions. Next, all leaves from tobacco plants grown under the iron-deficient condition
were excised. The expression of two genes were quickly reduced below half within 2 h after the leaf excision and gradually
disappeared by the end of a 24-h period. The NtIRT1 expression was compared among the plants whose leaves were cut off in various patterns. The expression increased in proportion
to the dry weight of iron-deficient leaves, although no relation was observed between the gene expression and the position
of excised leaves. Interestingly, the NtIRT1 expression in hairy roots increased under the iron-deficient condition, suggesting that roots also have the signaling mechanism
of iron status as well as shoots. Taken together, these results indicate that the long-distance signal generated in iron-deficient
tissues including roots is a major factor in positive regulation of the expression of NtIRT1 and NtFRO1 in roots, and that the strength of the signal depends on the size of plants. 相似文献
72.
Morimoto H Ozaki A Okamura H Yoshida K Amorim BR Tanaka H Kitamura S Haneji T 《Cell biochemistry and function》2007,25(4):369-375
In the present study, we examined the expression and cytolocalization of protein phosphatase type 1 (PP1) isoforms and nucleolin in human osteoblastic cell line MG63 cells at two boundaries in the cell cycle. We treated MG63 cells with hydroxyurea and nocodazole to arrest the cells at the G(1)/S and G(2)/M boundaries, respectively. As judged from the results of Western blot analysis, PP1 isoforms were expressed differently at each boundary of the cell cycle. Nucleolin was also shown to have a different expression pattern at each boundary. In the hydroxyurea-treated cells, nucleolus-like bodies were bigger in size and decreased in number compared with those in asynchronized cells. However, the subcellular localization of PP1s and nucleolin was not changed. Anti-nucleolin antibody interacted with 110-kDa and 95-kDa proteins present in asynchronized cells and in the cells treated with hydroxyurea. Treatment of the cells with nocodazole decreased the level of the 95-kDa form of nucleolin. In the nocodazole-treated cells, it was impossible to distinguish the distribution of each protein. The phosphorylation status of nucleolin in the cell cycle arrested samples was examined by 2D-IEF-PAGE followed by Western blot analysis. In the case of asynchronized cells or hydroxyurea-treated ones, nucleolin was located at a basic isoelectric point (dephosphorylated status); whereas in the G(2)/M arrest cells, the isoelectric point of nucleolin shifted to an acidic status, indicating that nucleolin was phosphorylated. The present results indicate that PP1 and nucleolin were differently expressed at G(1)/S and G(2)/M boundaries of the cell cycle and acted in a different fashion during cell-cycle progression. 相似文献
73.
Ikawa-Yoshida A Yoshii K Kuwahara K Obara M Kariwa H Takashima I 《Microbiology and immunology》2011,55(2):100-107
Tick-borne encephalitis (TBE) virus causes severe encephalitis with serious sequelae in humans. An epizootiological survey of wild rodents is effective to detect TBE virus-endemic areas; however, limited serological diagnostic methods are available to detect anti-TBE virus antibodies in wild rodents. In this study, ELISAs for the detection of rodent antibodies against the TBE virus were developed using two recombinant proteins, domain III of the E protein (EdIII) and subviral particles (SPs), as the antigens. As compared with the neutralization test, the ELISA using EdIII had 77.1% sensitivity and 80.0% specificity, and the ELISA using SPs had 91.4% sensitivity and 100% specificity. Furthermore, when the ELISAs were applied to the epizootiological survey in the TBE virus-endemic area, both of the ELISAs was able to detect wild rodents with TBE virus-specific antibodies. This is the first study to show that ELISAs using recombinant antigens can be safe and useful in the detection of TBE virus-infected wild rodents in epizootiological research. 相似文献
74.
Fujiwara Y Fujiwara K Goda N Iwaya N Tenno T Shirakawa M Hiroaki H 《The Journal of biological chemistry》2011,286(24):21732-21741
The N-terminal regions of AAA-ATPases (ATPase associated with various cellular activities) often contain a domain that defines the distinct functions of the enzymes, such as substrate specificity and subcellular localization. As described herein, we have determined the solution structure of an N-terminal unique domain isolated from nuclear valosin-containing protein (VCP)-like protein 2 (NVL2(UD)). NVL2(UD) contains three α helices with an organization resembling that of a winged helix motif, whereas a pair of β-strands is missing. The structure is unique and distinct from those of other known type II AAA-ATPases, such as VCP. Consequently, we identified nucleolin from a HeLa cell extract as a binding partner of this domain. Nucleolin contains a long (~300 amino acids) intrinsically unstructured region, followed by the four tandem RNA recognition motifs and the C-terminal glycine/arginine-rich domain. Binding analyses revealed that NVL2(UD) potentially binds to any of the combinations of two successive RNA binding domains in the presence of RNA. Furthermore, NVL2(UD) has a characteristic loop, in which the key basic residues RRKR are exposed to the solvent at the edge of the molecule. The mutation study showed that these residues are necessary and sufficient for nucleolin-RNA complex binding as well as nucleolar localization. Based on the observations presented above, we propose that NVL2 serves as an unfoldase for the nucleolin-RNA complex. As inferred from its RNA dependence and its ATPase activity, NVL2 might facilitate the dissociation and recycling of nucleolin, thereby promoting efficient ribosome biogenesis. 相似文献
75.
Kadirvelraj R Grant OC Goldstein IJ Winter HC Tateno H Fadda E Woods RJ 《Glycobiology》2011,21(7):973-984
Glycan chains that terminate in sialic acid (Neu5Ac) are frequently the receptors targeted by pathogens for initial adhesion. Carbohydrate-binding proteins (lectins) with specificity for Neu5Ac are particularly useful in the detection and isolation of sialylated glycoconjugates, such as those associated with pathogen adhesion as well as those characteristic of several diseases including cancer. Structural studies of lectins are essential in order to understand the origin of their specificity, which is particularly important when employing such reagents as diagnostic tools. Here, we report a crystallographic and molecular dynamics (MD) analysis of a lectin from Polyporus squamosus (PSL) that is specific for glycans terminating with the sequence Neu5Acα2-6Galβ. Because of its importance as a histological reagent, the PSL structure was solved (to 1.7??) in complex with a trisaccharide, whose sequence (Neu5Acα2-6Galβ1-4GlcNAc) is exploited by influenza A hemagglutinin for viral adhesion to human tissue. The structural data illuminate the origin of the high specificity of PSL for the Neu5Acα2-6Gal sequence. Theoretical binding free energies derived from the MD data confirm the key interactions identified crystallographically and provide additional insight into the relative contributions from each amino acid, as well as estimates of the importance of entropic and enthalpic contributions to binding. 相似文献
76.
Takahashi Y Daitoku H Yokoyama A Nakayama K Kim JD Fukamizu A 《Journal of receptor and signal transduction research》2011,31(2):168-172
Protein arginine methylation is a common post-translational modification in eukaryotes that is catalyzed by a family of the protein arginine methyltransferases (PRMTs). PRMTs are classified into three types: type I and type II add asymmetrically and symmetrically dimethyl groups to arginine, respectively, while type III adds solely monomethyl group to arginine. However, although the enzymatic activity of type I and type II PRMTs have been reported, the substrate specificity and the methylation activity of type III PRMTs still remains unknown. Here, we report the characterization of Caenorhabditis elegans PRMT-2 and PRMT-3, both of which are highly homologous to human PRMT7. We find that these two PRMTs can bind to S-adenosyl methionine (SAM), but only PRMT-3 has methyltransferase activity for histone H2A depending on its SAM-binding domain. Importantly, thin-layer chromatographic analysis demonstrates that PRMT-3 catalyzes the formation of monomethylated, but not dimethylated arginine. Our study thus identifies the first type III PRMT in C. elegans and provides a means to elucidate the physiological significance of arginine monomethylation in multicellular organisms. 相似文献
77.
Shindo K Tachibana A Tanaka A Toba S Yuki E Ozaki T Kumano T Nishiyama M Misawa N Kuzuyama T 《Bioscience, biotechnology, and biochemistry》2011,75(3):505-510
We performed combinational bioconversion of substituted naphthalenes with PhnA1A2A3A4 (an aromatic dihydroxylating dioxygenase from marine bacterium Cycloclasticus sp. strain A5) and prenyltransferase NphB (geranyltransferase from Streptomyces sp. strain CL190) or SCO7190 (dimethylallyltransferase from Streptomyces coelicolor A3(2)) to produce prenyl naphthalen-ols. Using 2-methylnaphthalene, 1-methoxynaphthalene, and 1-ethoxynaphthalene as the starting substrates, 10 novel prenyl naphthalen-ols were produced by combinational bioconversion. These novel prenyl naphthalen-ols each showed potent antioxidative activity against a rat brain homogenate model. 2-(2,3-Dihydroxyphenyl)-5,7-dihydroxy-chromen-4-one (2',3'-dihydroxychrysin) generated with another aromatic dihydroxylating dioxygenase and subsequent dehydrogenase was also geranylated at the C-5'-carbon by the action of NphB. 相似文献
78.
Predicting phenotypes using genome-wide genetic variation and gene expression data is useful in several fields, such as human biology and medicine, as well as in crop and livestock breeding. However, for phenotype prediction using gene expression data for mammals, studies remain scarce, as the available data on gene expression profiling are currently limited. By integrating a few sources of relevant data that are available in mice, this study investigated the accuracy of phenotype prediction for several physiological traits. Gene expression data from two tissues as well as single nucleotide polymorphisms (SNPs) were used. For the studied traits, the variance of the effects of the expression levels was more likely to differ among the genes than were the effects of SNPs. For the glucose concentration, the total cholesterol amount, and the total tidal volume, the accuracy by cross validation tended to be higher when the gene expression data rather than the SNP genotype data were used, and a statistically significant increase in the accuracy was obtained when the gene expression data from the liver were used alone or jointly with the SNP genotype data. For these traits, there were no additional gains in accuracy from using the gene expression data of both the liver and lung compared to that of individual use. The accuracy of prediction using genes that were selected differently was examined; the use of genes with a higher tissue specificity tended to result in an accuracy that was similar to or greater than that associated with the use of all of the available genes for traits such as the glucose concentration and total cholesterol amount. Although relatively few animals were evaluated, the current results suggest that gene expression levels could be used as explanatory variables. However, further studies are essential to confirm our findings using additional animal samples. 相似文献
79.
Toshimitsu Okeda Yasushi Yokogawa Hiroaki Ueo Mary A. Bury Paul O. P. Ts'o Sarah A. Bruce 《In vitro cellular & developmental biology. Plant》1990,26(12):1157-1166
Summary Primary cultures of 9-d-gestation Syrian hamster embryo (E9) cells are distinct from primary cultures of later gestational
age in terms of their growth and differentiation. First, primary E9 cell cultures express multiple mesenchymal differentiation
lineages (e.g., adipocyte, myoblast) only rarely seen in cultures of 13-d-gestation fetal (F13) cells. Second, although most
primary E9 cultures have a limited in vitro proliferative life span and exhibit cellular senescence similar to primary cultures
of F13 cells, E9 cultures seem to have higher frequency of escape from senescence and conversion to continuous cell lines
compared to F13 cells. Moreover, this frequency can be further increased 4- to 5-fold by continuous exposure of the E9 cells
to tumor promoters or epidermal growth factor. Eleven continuous cell lines have been isolated from unreated, promoter-treated,
or epidermal growth factor-treated primary E9 cultures. Seven of these are neoplastic or preneoplastic. However, the remaining
four do not show any evidence of being in neoplastic progression and three of these continue to express the same differentiated
phenotype observed in ther parental primary cell cultures.
These studies were supported in part by grants from the National Institutes of Health (AG 01998), Bethesda, MD, and the U.S.
Department of Energy (DE-A-C02-76-EVO-3280), Washington, DC. 相似文献
80.
Shigeki Suzuki Hiroaki Hoshino Kazuma Yoshida Jun Nakanishi Shizu Tsuchiya-Hirata Seiji Kobuke Naoto Haruyama Fusanori Nishimura Hideki Shiba 《Biochemical and biophysical research communications》2018,495(3):2303-2309
Chromatin-enriched noncoding RNAs (ncRNAs) have emerged as key molecules in epigenetic processes by interacting with chromatin-associated proteins. Recently, protein-coding mRNA genes have been reported to be chromatin-tethered, similar with ncRNA. However, very little is known about whether chromatin-enriched mRNA is involved in the chromatin modification process. Here, we comprehensively examined chromatin-enriched RNA in squamous cell carcinoma (SQCC) cells by RNA subcellular localization analysis, which was a combination of RNA fractionation and RNA-seq. We identified 11 mRNAs as highly chromatin-enriched RNAs. Among these, we focused on the dentin matrix protein-1 (DMP-1) gene because its expression in SQCC cells has not been reported. Furthermore, we clarified that DMP-1 mRNA was retained in chromatin in its unspliced form in SQCC in vitro and in vivo. As the inhibition of the unspliced DMP-1 mRNA (unspDMP-1) expression resulted in decreased cellular proliferation in SQCC cells, we performed ChIP-qPCR to identify cell cycle-related genes whose expression was epigenetically modified by unspDMP-1, and found that the CDKN1B promoter became active in SQCC cells by inhibiting unspDMP-1 expression. This result was further validated by the increased CDKN1B gene expression in the cells treated with siRNA for unspDMP-1 and by restoration of the decreased cellular proliferation rate by simultaneously inhibiting CDKN1B expression in SQCC cells. Further, to examine whether unspDMP-1 was able to associate with the CDKN1B promoter region, SQCC cells stably expressing PP7-mCherry fusion protein were transiently transfected with the unspDMP-1 fused to 24 repeats of the PP7 RNA stem loop (unspDMP-1-24xPP7) and we found that unspDMP-1-24xPP7 was efficiently precipitated with the antibody against mCherry and was significantly enriched in the CDKN1B promoter region. Thus, unspDMP-1 is a novel chromatin-enriched RNA that epigenetically regulates cellular proliferation of SQCC. 相似文献