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821.
Takao Koeduka Mami Kajiyama Hideyuki Suzuki Takumi Furuta Tomohiko Tsuge Kenji Matsui 《Planta》2016,244(3):725-736
822.
Selective depletion of high-avidity human immunodeficiency virus type 1 (HIV-1)-specific CD8+ T cells after early HIV-1 infection 下载免费PDF全文
Lichterfeld M Yu XG Mui SK Williams KL Trocha A Brockman MA Allgaier RL Waring MT Koibuchi T Johnston MN Cohen D Allen TM Rosenberg ES Walker BD Altfeld M 《Journal of virology》2007,81(8):4199-4214
Human immunodeficiency virus type 1 (HIV-1)-specific CD8+ T cells in early infection are associated with the dramatic decline of peak viremia, whereas their antiviral activity in chronic infection is less apparent. The functional properties accounting for the antiviral activity of HIV-1-specific CD8+ T cells during early infection are unclear. Using cytokine secretion and tetramer decay assays, we demonstrated in intraindividual comparisons that the functional avidity of HIV-1-specific CD8+ T cells was consistently higher in early infection than in chronic infection in the presence of high-level viral replication. This change of HIV-1-specific CD8+ T-cell avidity between early and chronic infections was linked to a substantial switch in the clonotypic composition of epitope-specific CD8+ T cells, resulting from the preferential loss of high-avidity CD8+ T-cell clones. In contrast, the maintenance of the initially recruited clonotypic pattern of HIV-1-specific CD8+ T cells was associated with low-level set point HIV-1 viremia. These data suggest that high-avidity HIV-1-specific CD8+ T-cell clones are recruited during early infection but are subsequently lost in the presence of persistent high-level viral replication. 相似文献
823.
Hosaka H Nagata A Yoshida T Shibata T Nagao T Tanaka T Saito Y Tatsuno I 《Peptides》2008,29(8):1390-1395
Although the neuropeptide Y (NPY) family has been demonstrated to control bone metabolism, the role of pancreatic polypeptide (PP), which has structural homology with NPY and peptide YY (PYY) to share the NPY family receptors, in peripheral bone tissues has remained unknown. In the present study, we studied the regulatory roles of PP and its Y receptors using MC3T3-E1 cells, a murine transformed osteoblastic cell line, as a model for osteoblastic differentiation. We found that (1) PP mRNA was detected and increased during cell-contact-induced differentiation in MC3T3-E1 cells; (2) the immunoreactivity of PP was detected by radioimmunoassay and increased in culture medium during differentiation; (3) all the types of NPY family receptor mRNAs (Y1, Y2, Y4, Y5, and y6) were found to increase during differentiation; (4) PP stimulated differentiation in MC3T3-E1 cells in terms of ALP mRNA and BMP-2 mRNA. These findings suggested that MC3T3-E1 cells produce and secrete PP, which may in turn stimulate the differentiation of MC3T3-E1 through its specific receptors in an autocrine manner. 相似文献
824.
Fukata Y Itoh TJ Kimura T Ménager C Nishimura T Shiromizu T Watanabe H Inagaki N Iwamatsu A Hotani H Kaibuchi K 《Nature cell biology》2002,4(8):583-591
Regulated increase in the formation of microtubule arrays is thought to be important for axonal growth. Collapsin response mediator protein-2 (CRMP-2) is a mammalian homologue of UNC-33, mutations in which result in abnormal axon termination. We recently demonstrated that CRMP-2 is critical for axonal differentiation. Here, we identify two activities of CRMP-2: tubulin-heterodimer binding and the promotion of microtubule assembly. CRMP-2 bound tubulin dimers with higher affinity than it bound microtubules. Association of CRMP-2 with microtubules was enhanced by tubulin polymerization in the presence of CRMP-2. The binding property of CRMP-2 with tubulin was apparently distinct from that of Tau, which preferentially bound microtubules. In neurons, overexpression of CRMP-2 promoted axonal growth and branching. A mutant of CRMP-2, lacking the region responsible for microtubule assembly, inhibited axonal growth and branching in a dominant-negative manner. Taken together, our results suggest that CRMP-2 regulates axonal growth and branching as a partner of the tubulin heterodimer, in a different fashion from traditional MAPs. 相似文献
825.
826.
Wu Y Siino JS Sugiyama T Kowalczykowski SC 《The Journal of biological chemistry》2006,281(52):40001-40009
We examined the double-stranded DNA (dsDNA) binding preference of the Saccharomyces cerevisiae Rad52 protein and its homologue, the Rad59 protein. In nuclease protection assays both proteins protected an internal sequence and the dsDNA ends equally well. Similarly, using electrophoretic mobility shift assays, we found the affinity of both Rad52 and Rad59 proteins for DNA ends to be comparable with their affinity for internal sequences. The protein-DNA complexes were also directly visualized using atomic force microscopy. Both proteins formed discrete complexes, which were primarily found (90-94%) at internal dsDNA sites. We also measured the DNA end binding behavior of human Rad52 protein and found a slight preference for dsDNA ends. Thus, these proteins have no strong preference for dsDNA ends over internal sites, which is inconsistent with their function at a step of dsDNA break repair that precedes DNA processing. Therefore, we conclude that S. cerevisiae Rad52 and Rad59 proteins and their eukaryotic counterparts function by binding to single-stranded DNA formed as intermediates of recombination rather than by binding to the unprocessed DNA double-strand break. 相似文献
827.
We previously reported that Arabidopsis indole-3-acetic acid (IAA)-methyltransferase-1 (IAMT1) catalyzes the conversion of IAA, an essential phytohormone, to methyl-IAA
(MeIAA) and that IAMT1 plays an important role in leaf development. Here, we present the possible mechanisms of action of MeIAA in Arabidopsis. We showed that MeIAA was more potent than IAA in the inhibition of hypocotyl elongation and that MeIAA and naphthalene-acetic
acid (NAA), but not IAA, rescued the hypocotyl gravitropic defects in dark-grown aux1. However, MeIAA was less potent than IAA in the inhibition of primary root elongation in light-grown seedlings, and could
not rescue the agravitropic root phenotype of aux1. MeIAA had a stronger capacity to induce lateral roots than both IAA and NAA and rescued the defective lateral root phenotype
of aux1 seedlings. However, its capacity to induce root hairs was weaker than IAA and NAA and did not rescue the defective root hair
phenotype of aux1 seedlings. These data indicate that MeIAA is an inactive form of IAA. The different sensitivities to MeIAA among different
organs probably resulted from different expression localization and capacities of a putative MeIAA esterase to convert MeIAA
to IAA. 相似文献
828.
829.
Mutations in rice (Oryza sativa) heavy metal ATPase 2 (OsHMA2) restrict the translocation of zinc and cadmium 总被引:4,自引:0,他引:4
Satoh-Nagasawa N Mori M Nakazawa N Kawamoto T Nagato Y Sakurai K Takahashi H Watanabe A Akagi H 《Plant & cell physiology》2012,53(1):213-224
Widespread soil contamination with heavy metals has fostered the need for plant breeders to develop new crops that do not accumulate heavy metals. Metal-transporting transmembrane proteins that transport heavy metals across the plant plasma membrane are key targets for developing these new crops. Oryza sativa heavy metal ATPase 3 (OsHMA3) is known to be a useful gene for limiting cadmium (Cd) accumulation in rice. OsHMA2 is a close homolog of OsHMA3, but the function of OsHMA2 is unknown. To gain insight into the function of OsHMA2, we analyzed three Tos17 insertion mutants. The translocation ratios of zinc (Zn) and Cd were clearly lower in all mutants than in the wild type, suggesting that OsHMA2 is a major transporter of Zn and Cd from roots to shoots. By comparing each allele in the OsHMA2 protein structure and measuring the Cd translocation ratio, we identified the C-terminal region as essential for Cd translocation into shoots. Two alleles were identified as good material for breeding rice that does not contain Cd in the grain but does contain some Zn, and that grows normally. 相似文献
830.
Eri Amasawa Tomohiko Ihara Keisuke Hanaki 《The International Journal of Life Cycle Assessment》2018,23(9):1874-1887