Functional non-equivalence of pollen ADF isovariants in Arabidopsis.

ADF/cofilin is a central regulator of actin dynamics. We previously demonstrated that two closely related Arabidopsis class IIa ADF isovariants, ADF7 and ADF10, are involved in the enhancement of actin turnover in pollen, but whether they have distinct functions remains unknown. Here, we further demonstrate that they exhibit distinct functions in regulating actin turnover both in vitro and in vivo. We found that ADF7 binds to ADP-G-actin with lower affinity, and severs and depolymerizes actin filaments less efficiently in vitro than ADF10. Accordingly, in pollen grains, ADF7 more extensively decorates actin filaments and is less freely distributed in the cytoplasm compared to ADF10. We further demonstrate that ADF7 and ADF10 show distinct intracellular localizations during pollen germination, and they have non-equivalent functions in promoting actin turnover in pollen. We thus propose that cooperation and labor division of ADF7 and ADF10 enable pollen cells to achieve exquisite control of the turnover of different actin structures to meet different cellular needs.

[E75, R78 and D82 of Escherichia coli FtsZ are key residues for FtsZ cellular self-assembly and FtsZ-MreB interaction].

OBJECTIVE: To explore effects of FtsZ mutants FtsZ(E75A), FtsZ(R78G) and FtsZ(D82A) on FtsZ self-assembly and interaction of FtsZ with MreB in Escherichia coli strains. METHODS) We constructed FtsZ and its mutant's plasmids by molecular clone and site-directed mutagenesis methods, and purified targeted proteins by affinity chromatography. QN6(ftsZ::yfp-cat), QN7(tsZ::yfp-cat), QN8(ftsZ(R78G)::yfp-cat) and QN9 (ftsZ(D82A):.:yfp-cat) strains were constructed by linear DNA homologous recombination. We observed cellular localization pattern of FtsZ and its mutants in E. coli by living cell imaging experiments, examined interaction of FtsZ/FtsZ*-FtsZ* and FtsZ/FtsZ*-MreB by Coimmunoprecipitation and bacteria two hybrid, and analyzed assembly characteristics of FtsZ mutants by Light scattering. RESULTS) The Yfp-labeled FtsZ(E75A), FtsZ(R78G) and FtsZ(D82A) mutant proteins failed to assemble into functional Z-ring structure and localize correctly in E. coli strains. Interaction of FtsZ with its mutants, or FtsZ*-FtsZ* and FtsZ*-MreB interaction were weakened or completely disappeared. In addition, in vitro experiments show that E75A, R78G and D82A mutations decreased the polymerization efficiency of FtsZ monomer. CONCLUSION: FtsZ E75, R78 and D82 are critical amino acids in the assembly, function of FtsZ protein and FtsZ-MreB interaction in E. coli strains.

Visualization and Quantification of the Dynamics of Actin Filaments in Arabidopsis Pollen Tubes.

The actin cytoskeleton plays an essential role in the regulation of polarized pollen tube growth, and its functions are dictated by its spatial organization and dynamics. Here we describe an assay to monitor the dynamics of actin filaments decorated with Lifeact-mEGFP in Arabidopsis pollen tubes using spinning disk confocal microscopy and measuring the parameters associated with their dynamics. The method allows us to assess the dynamics of actin filaments in growing Arabidopsis pollen tubes.

Identification of a Prognostic Signature Composed of GPI, IL22RA1, CCT6A and SPOCK1 for Lung Adenocarcinoma Based on Bioinformatic Analysis of lncRNA-Mediated ceRNA Network and Sample Validation.

Lung adenocarcinoma (LUAD) is one of the most common malignant tumors with high morbidity and mortality in China and worldwide. Long non-coding RNAs (lncRNAs) as the competing endogenous RNA (ceRNA) play an essential role in the occurrence and development of LUAD. However, identifying lncRNA-related biomarkers to improve the accuracy of LUAD prognosis remains to be determined. This study downloaded RNA sequence data from The Cancer Genome Atlas (TCGA) database and identified the differential RNAs by bioinformatics. A total of 214 lncRNA, 198 miRNA and 2989 mRNA were differentially identified between LUAD and adjacent nontumor samples. According to the ceRNA hypothesis, we constructed a lncRNA-miRNA-mRNA network including 95 protein-coding mRNAs, 7 lncRNAs and 15 miRNAs, and found 24 node genes in this network were significantly associated with the overall survival of LUAD patients. Subsequently, through LASSO regression and multivariate Cox regression analyses, a four-gene prognostic signature composed of GPI, IL22RA1, CCT6A and SPOCK1 was developed based on the node genes of the lncRNA-mediated ceRNA network, demonstrating high performance in predicting the survival and chemotherapeutic responses of low- and high-risk LUAD patients. Finally, independent prognostic factors were further analyzed and combined into a well-executed nomogram that showed strong potential for clinical applications. In summary, the data from the current study suggested that the four-gene signature obtained from analysis of lncRNA-mediated ceRNA could serve as a reliable biomarker for LUAD prognosis and evaluation of chemotherapeutic response.