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991.
Haruna Nakamura Mi-Rae Shin Takako Fukagawa Mami Arita Tatsuya Mikami Hiroaki Kodama 《Plant Cell, Tissue and Organ Culture》2014,116(1):47-53
A tobacco calmodulin-related protein, rgs-CaM, interacts with viral suppressors of RNA silencing and modulates host RNA silencing. Plants overexpressing the rgs-CaM gene were crossed with plants exhibiting sense transgene-induced RNA silencing (S-PTGS) or inverted repeat-induced RNA silencing (IR-PTGS). S44 plants harboring a sense transgene encoding a tobacco microsomal ω-3 fatty acide desaturase (NtFAD3) exhibited the S-PTGS phenotype. The frequency of the S-PTGS phenotype incidence was nearly 100 % in the hemizygous S44 plants, but was reduced to 30 % in crossbred plants with an rgs-CaM-overexpressing transgenic line. The remaining 70 % of crossbred plants successfully overexpressed the NtFAD3 transgene, and the amount of NtFAD3 small interfering RNAs (siRNAs) was largely decreased. In contrast, overexpression of rgs-CaM did not suppress siRNA production in the IR-PTGS that targeted the NtFAD3 gene. These results indicated that rgs-CaM suppresses RNA silencing at a step upstream of siRNA production and does not interfere with the later steps of RNA silencing, including siRNA-mediated RNA degradation. 相似文献
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Takako Ishida Yoshimasa Takizawa Takashi Kainuma Jin Inoue Tsutomu Mikawa Takehiko Shibata Hidekazu Suzuki Satoshi Tashiro Hitoshi Kurumizaka 《Nucleic acids research》2009,37(10):3367-3376
RAD51, an essential eukaryotic DNA recombinase, promotes homologous pairing and strand exchange during homologous recombination and the recombinational repair of double strand breaks. Mutations that up- or down-regulate RAD51 gene expression have been identified in several tumors, suggesting that inappropriate expression of the RAD51 activity may cause tumorigenesis. To identify chemical compounds that affect the RAD51 activity, in the present study, we performed the RAD51-mediated strand exchange assay in the presence of 185 chemical compounds. We found that 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS) efficiently inhibited the RAD51-mediated strand exchange. DIDS also inhibited the RAD51-mediated homologous pairing in the absence of RPA. A surface plasmon resonance analysis revealed that DIDS directly binds to RAD51. A gel mobility shift assay showed that DIDS significantly inhibited the DNA-binding activity of RAD51. Therefore, DIDS may bind near the DNA binding site(s) of RAD51 and compete with DNA for RAD51 binding. 相似文献
996.
Seiichi Tsukamoto Takako Yamashita Yoshiteru Yamada Kazuo Fujiwara Kosuke Maki Kunihiro Kuwajima Yoshitaka Matsumura Hiroshi Kihara Hideaki Tsuge Masamichi Ikeguchi 《Proteins》2009,76(1):226-236
Tear lipocalin and β‐lactoglobulin are members of the lipocalin superfamily. They have similar tertiary structures but unusually low overall sequence similarity. Non‐native helical structures are formed during the early stage of β‐lactoglobulin folding. To address whether the non‐native helix formation is found in the folding of other lipocalin superfamily proteins, the folding kinetics of a tear lipocalin variant were investigated by stopped‐flow methods measuring the time‐dependent changes in circular dichroism (CD) spectrum and small‐angle X‐ray scattering (SAXS). CD spectrum showed that extensive secondary structures are not formed during a burst‐phase (within a measurement dead time). The SAXS data showed that the radius of gyration becomes much smaller than in the unfolded state during the burst‐phase, indicating that the molecule is collapsed during an early stage of folding. Therefore, non‐native helix formation is not general for folding of all lipocalin family members. The non‐native helix content in the burst‐phase folding appears to depend on helical propensities of the amino acid sequence. Proteins 2009. © 2008 Wiley‐Liss, Inc. 相似文献
997.
Tetsuya Sakajiri Takaki Yamamura Takeshi Kikuchi Kaoru Ichimura Takako Sawada Hirofumi Yajima 《Biological trace element research》2010,136(3):279-286
Human transferrin (Tf) very tightly binds two ferric ions to deliver iron to cells. Fe(III)2Tf (Fe2Tf) binds to the Tf receptor (TfR) at pH 7.4; however, iron-free Tf (apoTf) does not. Iron uptake is facilitated by endocytosis of the Fe2Tf–TfR complex. Tf can also bind aluminum ions, which cause toxic effects and are associated with many diseases. Since Al(III)2Tf (Al2Tf) does not bind to TfR, the uptake of aluminum by the cells does not occur through a TfR-mediated pathway. We have studied the absence of binding between Al2Tf and TfR by investigating the physicochemical characteristics of apoTf, Al2Tf, Fe2Tf, and TfR. The hydrodynamic radius of 38.8 Å for Al2Tf obtained by dynamic light scattering was between that of 42.6 Å for apoTf and 37.2 Å for Fe2Tf. The ζ potential of ?11.3 mV for Al2Tf measured by capillary electrophoresis was close to ?11.2 mV for apoTf as compared to ?11.9 mV for Fe2Tf, indicating that the Al2Tf surface had a relatively scarce negative charge as the apoTf surface had. These results demonstrated that the structure of Al2Tf was a trade-off between the closed and open forms of Fe2Tf and apoTf, respectively. Consequently, it is suggested that Al2Tf cannot form specific ionic interresidual interactions, such as those formed by Fe2Tf, to bind to TfR, resulting in impossible complex formation between Al2Tf and TfR. 相似文献
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Theiler's murine encephalomyelitis virus is divided into two subgroups, TO and GDVII, inducing subgroup‐specific diseases. In order to investigate the role(s) of nonstructural proteins of TMEV, L and L*, leaders of two subgroups, were separately expressed with or without L* in BHK‐21 cells. Expression of L increased the number of apoptotic cells. L*/BHK‐21 cells constitutively expressing L* showed the decrease in cell death induced by L. These results suggest that L and L* regulate apoptosis during viral infection and contribute to TMEV subgroup‐specific biological activities. 相似文献
1000.
CRMP-2 is involved in kinesin-1-dependent transport of the Sra-1/WAVE1 complex and axon formation 下载免费PDF全文
Kawano Y Yoshimura T Tsuboi D Kawabata S Kaneko-Kawano T Shirataki H Takenawa T Kaibuchi K 《Molecular and cellular biology》2005,25(22):9920-9935
A neuron has two types of highly polarized cell processes, the single axon and multiple dendrites. One of the fundamental questions of neurobiology is how neurons acquire such specific and polarized morphologies. During neuronal development, various actin-binding proteins regulate dynamics of actin cytoskeleton in the growth cones of developing axons. The regulation of actin cytoskeleton in the growth cones is thought to be involved in axon outgrowth and axon-dendrite specification. However, it is largely unknown which actin-binding proteins are involved in axon-dendrite specification and how they are transported into the developing axons. We have previously reported that collapsin response mediator protein 2 (CRMP-2) plays a critical role in axon outgrowth and axon-dendrite specification (N. Inagaki, K. Chihara, N. Arimura, C. Menager, Y. Kawano, N. Matsuo, T. Nishimura, M. Amano, and K. Kaibuchi, Nat. Neurosci. 4:781-782, 2001). Here, we found that CRMP-2 interacted with the specifically Rac1-associated protein 1 (Sra-1)/WASP family verprolin-homologous protein 1 (WAVE1) complex, which is a regulator of actin cytoskeleton. The knockdown of Sra-1 and WAVE1 by RNA interference canceled CRMP-2-induced axon outgrowth and multiple-axon formation in cultured hippocampal neurons. We also found that CRMP-2 interacted with the light chain of kinesin-1 and linked kinesin-1 to the Sra-1/WAVE1 complex. The knockdown of CRMP-2 and kinesin-1 delocalized Sra-1 and WAVE1 from the growth cones of axons. These results suggest that CRMP-2 transports the Sra-1/WAVE1 complex to axons in a kinesin-1-dependent manner and thereby regulates axon outgrowth and formation. 相似文献