Functional characterization of TRICHOMELESS2, a new single-repeat R3 MYB transcription factor in the regulation of trichome patterning in Arabidopsis

<p>Abstract</p> <p>Background</p> <p>Single-repeat R3 MYB transcription factors (single-repeat MYBs) play important roles in controlling trichome patterning in <it>Arabidopsis</it>. It was proposed that single-repeat MYBs negatively regulate trichome formation by competing with GLABRA1 (GL1) for binding GLABRA3/ENHANCER OF GLABRA3 (GL3/EGL3), thus inhibiting the formation of activator complex TTG1(TRANSPARENT TESTA GLABRA1)-GL3/EGL3-GL1 that is required for the activation of <it>GLABRA2 </it>(<it>GL2</it>), whose product is a positive regulator of trichome formation. Previously we identified a novel single-repeat MYB transcription factor, TRICHOMELESS1 (TCL1), which negatively regulates trichome formation on the inflorescence stems and pedicels by directly suppressing the expression of <it>GL1</it>.</p> <p>Results</p> <p>We analyzed here the role of TRICHOMELESS2 (TCL2), a previously-uncharacterized single-repeat MYB transcription factor in trichome patterning in <it>Arabidopsis</it>. We showed that TCL2 is closely related to TCL1, and like TCL1 and other single-repeat MYBs, TCL2 interacts with GL3. Overexpression of <it>TCL2 </it>conferred glabrous phenotype while knockdown of <it>TCL2 </it>via RNAi induced ectopic trichome formation on the inflorescence stems and pedicels, a phenotype that was previously observed in <it>tcl1 </it>mutants. These results suggested that TCL2 may have overlapping function with TCL1 in controlling trichome formation on inflorescences. On the other hand, although the transcription of <it>TCL2</it>, like <it>TCL1, </it>is not controlled by the activator complex formed by GL1 and GL3, and TCL2 and TCL1 proteins are more than 80% identical at the amino acid level, the expression of <it>TCL2 </it>under the control of <it>TCL1 </it>promoter only partially recovered the mutant phenotype of <it>tcl1</it>, implying that TCL2 and TCL1 are not fully functional equivalent.</p> <p>Conclusions</p> <p>TCL2 function redundantly with TCL1 in controlling trichome formation on inflorescences, but they are not fully functional equivalent. Transcription of <it>TCL2 </it>is not controlled by activator complex formed by GL1 and GL3, but <it>MIR156 </it>controlled SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) transcription factors. However, SPLs might require co-activators to regulate the expression of their target genes, including <it>TCL1</it>, <it>TRY </it>and possibly, <it>TCL2</it>.</p

Association between Polymorphisms of ERCC1 and Response in Patients with Advanced Non-small Cell Lung Cancer Receiving Cisplatin-based Chemotherapy

Background and objective Results of studies on genetic polymorphisms of ERCC1 gene in DNA repair pathway which may affect response to platinum-based chemotherapy and survival in patients with non-small cell lung cancer are conflicting. The aim of this study is to prospectively assess the association between single nucleotide polymorphisms of C8092A and codon118 in ERCC1 and drug response in 90 patients with advanced non-small cell lung cancer treated with cisplatin-based chemotherapy. Methods All patients were treated with cisplatin-based chemotherapy. Genotypes of ERCC1 C8092A and codon118 were examined by sequencing, and the association between genotypes and response was evaluated. Results Genotype frequencies of ERCC1 C8092A were CC 40.0% (36/90), CA 48.9% (44/90) and AA 11.1% (10/90), frequencies of codon118 were CC 58.9% (53/90), CT 34.4% (31/90) and TT 6.7% (6/90). There was no significant difference in response rate of patients carrying with CC, compared with CA plus AA in C8092A (33.3% vs 29.6%, P=0.71). Response rate of patients carrying with CC in ERCC1 118 was 32.1%, 24.3% with CT plus CC (P=0.43). There was no difference in progression free survival between patients carrying with CC and CT plus TT in C8092A (5.2 months vs 5.4 months, P=0.62). There was no difference in progression free survival between patients carrying with CC and CA plus AA (5.5 months vs 5.3 months, P=0.59). Conclusion The results suggest that there is no association between polymorphisms in ERCC1 C8092A and codon118 and response in patients with advanced non-small cell lung cancer receiving cisplatin-based chemotherapy

Advanced Feedback Experiment Methods With Hiher Education Theory

Advanced reserved experiment method focused cognitive law, constructivism and assimilation theory in a way that science teaching method has a profound theoretical foundation and many years of teaching practice. It is a product of deepening the reform of higher education, it is a method of quality education, innovative ability indispensable.The advanced feedback experimental method, that is, to arrange the experimental activity ahead of teaching the theory, so that students can find problems in the course of experiment and solve them in the follow-up theory teaching, it is able to fully mobilize the enthusiasm of students and let them be full of “suspense” before the class. The biggest advantage of the advanced feedback experimental method is to provide more supports to the heuristic and interactive teaching. It enables students to get the maximum amount of information of physics, chemistry, biology and other natural phenomena within limited time and space and in turn to co-operate the classroom teaching strongly. The “hide” of experimental class and the “show” of theory teaching echo each other to make the experiment and theory class linked organically. That can stir up students’ interests and passion in learning. So that they have “Suspense” before class, after-class sense of accomplishment. After more than ten years of practice, it proves that the advanced feedback experimental method is indeed a good way to reform the professional of natural science for higher education sectionand. It is worthy for recommendation

A single amino acid substitution in the R3 domain of GLABRA1 leads to inhibition of trichome formation in Arabidopsis without affecting its interaction with GLABRA3

GLABRA1 (GL1) is an R2R3 MYB transcription factor that regulates trichome formation in Arabidopsis by interacting with the bHLH transcription factor GLABRA3 (GL3) or ENHANCER OF GL3 (EGL3). The conserved [D/E]L×2 [R/K]×3L×6L×3R amino acid signature in the R3 domain of MYB proteins has been shown to be required for the interaction of MYBs with R/B‐like bHLH transcription factors. By using genetic and molecular analyses, we show that the glabrous phenotype in the nph4‐1 mutant is caused by a single nucleotide mutation in the GL1 gene, generating a Ser to Phe substitution (S92F) in the conserved [D/E]L×2[R/K]×3L×6L×3R amino acid signature of GL1. Activation of the integrated GL2p:GUS reporter gene in protoplasts by cotransfection of GL1 and GL3 or EGL3 was abolished by this GL1‐S92F substitution. However, GL1‐S92F interacted successfully with GL3 or EGL3 in protoplast transfection assays. Unlike VPGL1GL3, the fusion protein VPGL1‐S92FGL3 failed to activate the integrated GL2p:GUS reporter gene in transfected protoplasts. These results suggested that the S92 in the conserved [D/E]L×2 [R/K]×3L×6L×3R amino acid signature of GL1 is not essential for the interaction of GL1 and GL3, but may play a role in the binding of GL1 to the promoters of its target genes.The R2R3 MYB transcription factor GL1 is a key regulator of trichome formation in Arabidopsis. The conserved [D/E]L×2[R/K]×3L×6L×3R amino acid signature in the R3 domain is required for the interaction of MYBs with R/B‐like bHLH transcription factors. S92F amino acid substantiation in the conserved [D/E]L×2[R/K]×3L×6L×3R signature in GL1 lead to loss‐of‐function mutation of GL1. However, our results indicate that Ser92 residue is not required for the interaction of GL1 with bHLH transcription factor GL3 or EGL3, but may required for binding of GL1 to its target genes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145310/1/pce12695_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145310/2/pce12695.pd

Parameters Optimization of Curtain Grouting Reinforcement Cycle in Yonglian Tunnel and Its Application

For practical purposes, the curtain grouting method is an effective method to treat geological disasters and can be used to improve the strength and permeability resistance of surrounding rock. Selection of the optimal parameters of grouting reinforcement cycle especially reinforcement cycle thickness is one of the most interesting areas of research in curtain grouting designs. Based on the fluid-structure interaction theory and orthogonal analysis method, the influence of reinforcement cycle thickness, elastic modulus, and permeability on water inflow of tunnel after grouting and stability of surrounding rock was analyzed. As to the water inflow of tunnel after grouting used as performance evaluation index of grouting reinforcement cycle, it can be concluded that the permeability was the most important factor followed by reinforcement cycle thickness and elastic modulus. Furthermore, pore water pressure field, stress field, and plastic zone of surrounding rock were calculated by using COMSOL software under different conditions of reinforcement cycle thickness. It also can be concluded that the optimal thickness of reinforcement cycle and permeability can be adopted as 8 m and 1/100 of the surrounding rock permeability in the curtain grouting reinforcement cycle. The engineering case provides a reference for similar engineering

The R2R3-MYB Factor FhMYB5 From Freesia hybrida Contributes to the Regulation of Anthocyanin and Proanthocyanidin Biosynthesis

The flavonoids are important and nourishing compounds for plants and human. The transcription regulation of anthocyanin and proanthocyanidin (PA) biosynthesis was extensively studied in dicot compared with monocot plants. In this study, we characterized the functionality of an R2R3-MYB gene FhMYB5 from the monocotyledonous flowering plant of Iridaceae, Freesia hybrida. Multiple sequence alignment and phylogenetic analysis implied that FhMYB5 was clustered into grapevine VvMYB5b subclade. Correlation analysis indicated that the spatio-temporal expression patterns of FhMYB5 coincided well with anthocyanin and PA accumulations in Freesia per se. Furthermore, transient transfection assays in Freesia protoplasts revealed that the late flavonoid biosynthetic genes (e.g., DFR and LDOX) were slightly up-regulated by FhMYB5 alone, whereas both early and late biosynthetic genes were significantly activated when FhMYB5 were co-infected with either of the two IIIf clade bHLH genes, FhTT8L and FhGL3L. Moreover, these results were further confirmed by co-transfection of FhMYB5 with either of the bHLH genes aforementioned into protoplasts expressing GUS reporter gene driven by Freesia promoters. In addition, the overexpression of FhMYB5 in tobacco and Arabidopsis could also significantly up-regulate the expression of genes participating in the general flavonoid pathway. In conclusion, FhMYB5 was proved to function in the general flavonoid pathway in Freesia. The results implied a function conservation of flavonoid biosynthesis related MYB regulators in angiosperm plants

PCSK9 regulates the efficacy of immune checkpoint therapy in lung cancer

Proprotein convertase subtilisin/kexin type 9 (PCSK9) secreted by tumors was reported as a deleterious factor that led to the reduction of lymphocyte infiltration and the poorer efficacy of ICIs in vivo. This study aimed to explore whether PCSK9 expression in tumor tissue could predict the response of advanced non-small cell lung cancer (NSCLC) to anti-PD-1 immunotherapy and the synergistic antitumor effect of the combination of the PCSK9 inhibitor with the anti-CD137 agonist. One hundred fifteen advanced NSCLC patients who received anti-PD-1 immunotherapy were retrospectively studied with PCSK9 expression in baseline NSCLC tissues detected by immunohistochemistry (IHC). The mPFS of the PCSK9lo group was significantly longer than that of the PCSK9hi group [8.1 vs. 3.6 months, hazard ratio (HR): 3.450; 95% confidence interval (CI), 2.166-5.496]. A higher objective response rate (ORR) and a higher disease control rate (DCR) were observed in the PCSK9lo group than in the PCSK9hi group (54.4% vs. 34.5%, 94.7% vs. 65.5%). Reduction and marginal distribution of CD8+ T cells were observed in PCSK9hi NSCLC tissues. Tumor growth was retarded by the PCSK9 inhibitor and the anti-CD137 agonist alone in the Lewis lung carcinoma (LLC) mice model and further retarded by the PCSK9 inhibitor in combination with the CD137 agonist with long-term survival of the host mice with noticeable increases of CD8+ and GzmB+ CD8+ T cells and reduction of Tregs. Together, these results suggested that high PCSK9 expression in baseline tumor tissue was a deleterious factor for the efficacy of anti-PD-1 immunotherapy in advanced NSCLC patients. The PCSK9 inhibitor in combination with the anti-CD137 agonist could not only enhance the recruitment of CD8+ and GzmB+ CD8+ T cells but also deplete Tregs, which may be a novel therapeutic strategy for future research and clinical practice

Distinct relationships between GLABRA2 and single-repeat R3 MYB transcription factors in the regulation of trichome and root hair patterning in Arabidopsis

• The patterning of epidermal cell types in Arabidopsis is an excellent model for studying the molecular basis of cell specification. Trichome and root hair formation is controlled by a transcriptional activator complex that induces the homeobox gene GLABRA2 (GL2) and some single-repeat R3 MYB genes (single MYB ). However, it remains unclear how the actions of GL2 and single MYBs are coordinated to regulate epidermal patterning. • GL2 is thought to act downstream of single MYBs to regulate trichome and root hair development. In order to test this hypothesis genetically, double and higher order mutants between gl2 and single myb were generated. • In these mutants, the glabrous phenotypes observed in the gl2 single mutants were partially recovered, suggesting that single MYBs may not act solely through GL2 to regulate trichome development. On the other hand, double and higher order mutants between gl2 and single myb phenocopied the root hair phenotype of gl2 single mutants, suggesting that GL2 and single MYBs act in a common pathway to regulate root hair patterning. • These findings reveal distinct relationships between GL2 and single MYBs in the regulation of trichome vs root hair development, and provide new insights into the molecular mechanism of epidermal patterning.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78641/1/j.1469-8137.2009.03067.x.pd