In the past decade, significant knowledge has accumulated regarding gibberellin （GA） signal transductlon In rice as a result of studies using multiple approaches, particularly molecular genetics. The present review ...In the past decade, significant knowledge has accumulated regarding gibberellin （GA） signal transductlon In rice as a result of studies using multiple approaches, particularly molecular genetics. The present review highlights the recent developments In the identification of GA signaling pathway components, the discovery of GA-Induced destructlon of GA signaling repressor （DELLA protein）, and the possible mechanism underlying the regulation of GA- responsive gene expression in rice.展开更多
Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that underg...Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS （Nuclear Localization Signal） sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2Ks41R and CRY2K554/sR mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/sR mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.展开更多
Studies on rodents and humans demonstrate an inherited predisposition to hepatocellular carcinoma （HCC）. Analysis of the molecular alterations involved in the acquisition of a phenotype resistant or susceptible to h...Studies on rodents and humans demonstrate an inherited predisposition to hepatocellular carcinoma （HCC）. Analysis of the molecular alterations involved in the acquisition of a phenotype resistant or susceptible to hepatocarcinogenesis showed a deregulation of G1 and S phases in HCC of genetically susceptible F344 rats and a G1-S block in lesions of resistant Brown norway （BN） rats. Unrestrained extracellular signal-regulated kinase （ERK） activity linked to proteasomal degradation of dual-specificity phosphatase 1 （DUSP1）, a specific ERK inhibitor, by the CKS1-SKP2 ubiquitin ligase complex occurs in more aggressive HCC of F344 rats and humans. This mechanism is less active in HCC of BN rats and human HCC with better prognosis. Upregulation of iNos cross-talk with IKK/NF-KB and RAS/ERK pathways occurs in rodent liver lesions at higher levels in the most aggressive models represented by HCC of F344 rats and c-Myc-TGF-α transgenic mice. iNOS, IKK/NF-κB, and RAS/ERK upregulation is highest in human HCC with a poorer prognosis and positively correlates with tumor proliferation, genomic instability and microvascularization, and negatively with apoptosis. Thus, cell cycle regulation and the activity of signal transduction pathways seem to be modulated by HCC modifier genes, and differences in their efficiency influence the susceptibility to hepatocarcinogenesis and probably the prognosis of human HCC.展开更多
The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degra...The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient- loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio （PSNR） is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2 - 1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.展开更多
Aiming at coherence degradation during target detection,a suppressing method based on frequency-modulated continuous wave coherent lidar is proposed.Combined with a random iteration algorithm,a long-pulse echo signal ...Aiming at coherence degradation during target detection,a suppressing method based on frequency-modulated continuous wave coherent lidar is proposed.Combined with a random iteration algorithm,a long-pulse echo signal with coherent degradation is matched with random phase noise of a certain frequency and achieves coherence restoration.Simulation and field experiment results show that this proposed method can recover the intrapulse coherence in long-pulse echo signals.In addition,for the real target echo signal at 4.2 and 19.8 km,the peak signal-to-noise ratio processed by this method is increased by 0.35 times and 4 times after pulse compression,respectively.展开更多
Human SAMHD1(h SAM)restricts lentiviruses at the reverse transcription step through its d NTP triphosphohydrolase(d NTPase)activity.Besides humans,several mammalian species such as cats and cows that carry their own l...Human SAMHD1(h SAM)restricts lentiviruses at the reverse transcription step through its d NTP triphosphohydrolase(d NTPase)activity.Besides humans,several mammalian species such as cats and cows that carry their own lentiviruses also express SAMHD1.However,the intracellular distribution of feline and bovine SAMHD1(f SAM and b SAM)and its significance in their lentiviral restriction function is not known.Here,we demonstrated that f SAM and b SAM were both predominantly localized to the nucleus and nuclear localization signal(11KRPR14)-deleted f SAM and b SAM relocalized to the cytoplasm.Both cytoplasmic f SAM and b SAM retained the antiviral function against different lentiviruses and cytoplasmic f SAM could restrict Vpx-encoding SIV and HIV-2 more efficiently than its wild-type(WT)protein as cytoplasmic h SAM.Further investigation revealed that cytoplasmic f SAM was resistant to Vpx-induced degradation like cytoplasmic h SAM,while cytoplasmic b SAM was not,but they all demonstrated the same in vitro d NTPase activity and all could interact with Vpx as their WT proteins,indicating that cytoplasmic h SAM and f SAM can suppress more SIV and HIV-2 by being less sensitive to Vpx-mediated degradation.Our results suggested that f SAM-and b SAM-mediated lentiviral restriction does not require their nuclear localization and that f SAM shares more common features with h SAM.These findings may provide insights for the establishment of alternative animal models to study SAMHD1 in vivo.展开更多
SKIP is a conserved protein from yeasts to plants and humans. In plant cells, SKIP is a bifunctional regulator that works in the nucleus as a splicing factor by integrating into the spliceosome and as a transcriptiona...SKIP is a conserved protein from yeasts to plants and humans. In plant cells, SKIP is a bifunctional regulator that works in the nucleus as a splicing factor by integrating into the spliceosome and as a transcriptional activator by interacting with the Pall complex. In this study, we identified two nuclear localization signals in SKIP and confirmed that each is sufficient to target SKIP to the nucleus. The SNW domain of SKIP is required for both its function as a splicing factor by promoting integration into the spliceosome in response to stress, and its function as a transcriptional activator by controlling its interaction with the Pall complex to participate in flowering. Truncated proteins that included the SNW domain and the N- or C-terminus of SKIP were still able to carry out the functions of the full-length protein in gene splicing and transcriptional activation in Arabidopsis. In addition, we found that SKIP undergoes 26S proteasome-mediated degrada- tion, and that the C-terminus of SKIP is required to maintain the stability of the protein in plant cells. Together, our findings demonstrate the structural domain organization of SKIP and reveal the core domains and motifs underlying SKIP function in plants.展开更多
基金Publication of this paper is supported by the National Natural Science Foundation of China （30624808）.
文摘In the past decade, significant knowledge has accumulated regarding gibberellin （GA） signal transductlon In rice as a result of studies using multiple approaches, particularly molecular genetics. The present review highlights the recent developments In the identification of GA signaling pathway components, the discovery of GA-Induced destructlon of GA signaling repressor （DELLA protein）, and the possible mechanism underlying the regulation of GA- responsive gene expression in rice.
基金the National Institute of Health，the National Natural Science Foundation of China，National Transgenic Crop Initiative
文摘Arabidopsis cryptochrome 2 （CRY2） is a blue-light receptor mediating blue-light inhibition of hypocotyl elongation and photoperiodic promotion of floral initiation. CRY2 is a constitutive nuclear protein that undergoes blue-light-dependent phosphorylation, ubiquitination, photobody formation, and degradation in the nucleus, but the relationship between these blue-light-dependent events remains unclear. It has been proposed that CRY2 phosphorylation triggers a conformational change responsible for the subsequent ubiquitination and photobody formation, leading to CRY2 function and/or degradation. We tested this hypothesis by a structure-function study, using mutant CRY2-GFP fusion proteins expressed in transgenic Arabidopsis. We show that changes of lysine residues of the NLS （Nuclear Localization Signal） sequence of CRY2 to arginine residues partially impair the nuclear importation of the CRY2Ks41R and CRY2K554/sR mutant proteins, resulting in reduced phosphorylation, physiological activities, and degradation in response to blue light. In contrast to the wild-type CRY2 protein that forms photobodies exclusively in the nucleus, the CRY2K541R and CRY2K554/sR mutant proteins form protein bodies in both the nucleus and cytosol in response to blue light. These results suggest that photoexcited CRY2 molecules can aggregate to form photobody-like structure without the nucleus-dependent protein modifications or the association with the nuclear CRY2-interacting proteins. Taken together, the observation that CRY2 forms photobodies markedly faster than CRY2 phosphorylation in response to blue light, we hypothesize that the photoexcited cryptochromes form oligomers, preceding other biochemical changes of CRY2, to facilitate photobody formation, signal amplification, and propagation, as well as desensitization by degradation.
基金Supported by Grants from the"Associazione Italiana Ricerche sul Cancro"
文摘Studies on rodents and humans demonstrate an inherited predisposition to hepatocellular carcinoma （HCC）. Analysis of the molecular alterations involved in the acquisition of a phenotype resistant or susceptible to hepatocarcinogenesis showed a deregulation of G1 and S phases in HCC of genetically susceptible F344 rats and a G1-S block in lesions of resistant Brown norway （BN） rats. Unrestrained extracellular signal-regulated kinase （ERK） activity linked to proteasomal degradation of dual-specificity phosphatase 1 （DUSP1）, a specific ERK inhibitor, by the CKS1-SKP2 ubiquitin ligase complex occurs in more aggressive HCC of F344 rats and humans. This mechanism is less active in HCC of BN rats and human HCC with better prognosis. Upregulation of iNos cross-talk with IKK/NF-KB and RAS/ERK pathways occurs in rodent liver lesions at higher levels in the most aggressive models represented by HCC of F344 rats and c-Myc-TGF-α transgenic mice. iNOS, IKK/NF-κB, and RAS/ERK upregulation is highest in human HCC with a poorer prognosis and positively correlates with tumor proliferation, genomic instability and microvascularization, and negatively with apoptosis. Thus, cell cycle regulation and the activity of signal transduction pathways seem to be modulated by HCC modifier genes, and differences in their efficiency influence the susceptibility to hepatocarcinogenesis and probably the prognosis of human HCC.
基金the National Key Lab-oratory Scientific Foundation of Optical Signature of Targets and Environments and Cultivation Fund of the Key Scientific and Technical Project,Ministry of Educa-tion of China (No.706022).
文摘The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient- loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio （PSNR） is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2 - 1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.
基金supported by the National Key Research and Development Program of China(No.2020YFB0408302)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB43030400)。
文摘Aiming at coherence degradation during target detection,a suppressing method based on frequency-modulated continuous wave coherent lidar is proposed.Combined with a random iteration algorithm,a long-pulse echo signal with coherent degradation is matched with random phase noise of a certain frequency and achieves coherence restoration.Simulation and field experiment results show that this proposed method can recover the intrapulse coherence in long-pulse echo signals.In addition,for the real target echo signal at 4.2 and 19.8 km,the peak signal-to-noise ratio processed by this method is increased by 0.35 times and 4 times after pulse compression,respectively.
基金funded by the National Natural Science Foundation of China(31270807)the Key Projects in the National Science&Technology Pillar Program in the Thirteenth Five-year Plan Period(2018ZX10731101-002-003 and 2018ZX10731101-001-020)+3 种基金Program for Jilin University Science and Technology Innovative Research Team(JLUSTIRT)(2017TD05)National Postdoctoral Program for Innovative Talents(BX20180124)China Postdoctoral Science Foundation(2018M641786)Science and Technology Development Project of Jilin Province(20200901030SF)。
文摘Human SAMHD1(h SAM)restricts lentiviruses at the reverse transcription step through its d NTP triphosphohydrolase(d NTPase)activity.Besides humans,several mammalian species such as cats and cows that carry their own lentiviruses also express SAMHD1.However,the intracellular distribution of feline and bovine SAMHD1(f SAM and b SAM)and its significance in their lentiviral restriction function is not known.Here,we demonstrated that f SAM and b SAM were both predominantly localized to the nucleus and nuclear localization signal(11KRPR14)-deleted f SAM and b SAM relocalized to the cytoplasm.Both cytoplasmic f SAM and b SAM retained the antiviral function against different lentiviruses and cytoplasmic f SAM could restrict Vpx-encoding SIV and HIV-2 more efficiently than its wild-type(WT)protein as cytoplasmic h SAM.Further investigation revealed that cytoplasmic f SAM was resistant to Vpx-induced degradation like cytoplasmic h SAM,while cytoplasmic b SAM was not,but they all demonstrated the same in vitro d NTPase activity and all could interact with Vpx as their WT proteins,indicating that cytoplasmic h SAM and f SAM can suppress more SIV and HIV-2 by being less sensitive to Vpx-mediated degradation.Our results suggested that f SAM-and b SAM-mediated lentiviral restriction does not require their nuclear localization and that f SAM shares more common features with h SAM.These findings may provide insights for the establishment of alternative animal models to study SAMHD1 in vivo.
文摘SKIP is a conserved protein from yeasts to plants and humans. In plant cells, SKIP is a bifunctional regulator that works in the nucleus as a splicing factor by integrating into the spliceosome and as a transcriptional activator by interacting with the Pall complex. In this study, we identified two nuclear localization signals in SKIP and confirmed that each is sufficient to target SKIP to the nucleus. The SNW domain of SKIP is required for both its function as a splicing factor by promoting integration into the spliceosome in response to stress, and its function as a transcriptional activator by controlling its interaction with the Pall complex to participate in flowering. Truncated proteins that included the SNW domain and the N- or C-terminus of SKIP were still able to carry out the functions of the full-length protein in gene splicing and transcriptional activation in Arabidopsis. In addition, we found that SKIP undergoes 26S proteasome-mediated degrada- tion, and that the C-terminus of SKIP is required to maintain the stability of the protein in plant cells. Together, our findings demonstrate the structural domain organization of SKIP and reveal the core domains and motifs underlying SKIP function in plants.
