Characterization of Genes Encoding Poly(A) Polymerases in Plants: Evidence for Duplication and Functional Specialization

BACKGROUND:Poly(A) polymerase is a key enzyme in the machinery that mediates mRNA 3' end formation in eukaryotes. In plants, poly(A) polymerases are encoded by modest gene families. To better understand this multiplicity of genes, poly(A) polymerase-encoding genes from several other plants, as well as from Selaginella, Physcomitrella, and Chlamydomonas, were studied. METHODOLOGY/PRINCIPAL FINDINGS:Using bioinformatics tools, poly(A) polymerase-encoding genes were identified in the genomes of eight species in the plant lineage. Whereas Chlamydomonas reinhardtii was found to possess a single poly(A) polymerase gene, other species possessed between two and six possible poly(A) polymerase genes. With the exception of four intron-lacking genes, all of the plant poly(A) polymerase genes (but not the C. reinhardtii gene) possessed almost identical intron positions within the poly(A) polymerase coding sequences, suggesting that all plant poly(A) polymerase genes derive from a single ancestral gene. The four Arabidopsis poly(A) polymerase genes were found to be essential, based on genetic analysis of T-DNA insertion mutants. GFP fusion proteins containing three of the four Arabidopsis poly(A) polymerases localized to the nucleus, while one such fusion protein was localized in the cytoplasm. The fact that this latter protein is largely pollen-specific suggests that it has important roles in male gametogenesis. CONCLUSIONS/SIGNIFICANCE:Our results indicate that poly(A) polymerase genes have expanded from a single ancestral gene by a series of duplication events during the evolution of higher plants, and that individual members have undergone sorts of functional specialization so as to render them essential for plant growth and development. Perhaps the most interesting of the plant poly(A) polymerases is a novel cytoplasmic poly(A) polymerase that is expressed in pollen in Arabidopsis; this is reminiscent of spermatocyte-specific cytoplasmic poly(A) polymerases in mammals

INFLUENCE TECHNIQUE VS IDEAL MODEL ON CREDIBILITY THEORY DISTRIBUTIONS RATIOS: A CASE STUDY OF TRIPLE JUMP

The objective of this study is to describe and compare the techniques used by elite triple jumpers in the world to determine the impact of the modality distribution ratios in achieving results. Our subjects were the 2009-2011 global elite’s finalists with five (5) Algerian amateur athletes. In the absence of technological methods in Algeria, our study explores the reports (IAAF): 1. To describe the phase distribution of the practice model between our world champions (2009 and 2011) 2. To compare the credibility theory of distributions ratio achievement with the modality dominant techniques practiced by champions (2009 and 2011). 3. To answer this question: can we consider the phase difference ratios as a bad distribution error in the technical ideal? As a result, we chose the analysis of variance and the correlation of relative distances obtained from each phase of the official distance achieved by the athlete. For the study statistics, our used data is based on the "t" independent method compared to the impact phase distributions (hop, step, and jump) charged with the results achieved in the test. However, our goal for this research is: • Using biomechanics to determine errors and integrate the modern scientific methods in monitoring the athletic program. • To allow our elites and their coaches to examine the impact of modality distribution ratios in achieving results in order to choose the good combined efforts and the selected template model practiced to improve the best performance in training and competition

INFLUENCE TECHNIQUE VS IDEAL MODEL ON CREDIBILITY THEORY DISTRIBUTIONS RATIOS: A CASE STUDY OF TRIPLE JUMP

The objective of this study is to describe and compare the techniques used by elite triple jumpers in the world to determine the impact of the modality distribution ratios in achieving results. Our subjects were the 2009-2011 global elite’s finalists with five (5) Algerian amateur athletes. In the absence of technological methods in Algeria, our study explores the reports (IAAF): 1. To describe the phase distribution of the practice model between our world champions (2009 and 2011) 2. To compare the credibility theory of distributions ratio achievement with the modality dominant techniques practiced by champions (2009 and 2011). 3. To answer this question: can we consider the phase difference ratios as a bad distribution error in the technical ideal? As a result, we chose the analysis of variance and the correlation of relative distances obtained from each phase of the official distance achieved by the athlete. For the study statistics, our used data is based on the "t" independent method compared to the impact phase distributions (hop, step, and jump) charged with the results achieved in the test. However, our goal for this research is: • Using biomechanics to determine errors and integrate the modern scientific methods in monitoring the athletic program. • To allow our elites and their coaches to examine the impact of modality distribution ratios in achieving results in order to choose the good combined efforts and the selected template model practiced to improve the best performance in training and competition

Decent work, financial inclusion, and economic growth: Analysis under the SDG 8

We investigate the potential influence of decent work and financial inclusion on economic growth, aligning our analysis with the United Nations Sustainable Development Goal 8 (SDG 8). Analyzing a diverse set of 26 low-income, 20 middle-income, and 15 high-income countries, we utilize a dynamic fixed-effect panel data approach and apply the Generalized Method of Moments from 2010 to 2021. The findings highlight that favorable conditions for decent work and increased access to digital financial services contribute positively to economic growth. The synergistic effect of these SDG 8 components is notably pronounced in high-income countries, with greater potential for elevated economic growth rates. Conversely, no discernible impact is observed on the economic growth of low-income countries. The results for middle-income countries present nuanced coefficient outcomes, offering a more intricate interpretation of their economic dynamics. An extensive impulse-response analysis, conducted using a Panel Vector Autoregression model, demonstrates distinct impacts of shocks related to decent work and financial inclusion across various income categories of countries. Our findings pass various robustness checks, affirming their reliability and suggesting significant policy implications for recognizing the crucial role of decent work and financial inclusion in fostering economic growth. 

HAWAIIAN SKIRT, and F-box gene from Arabidopsis, is a new player in the microRNA pathway

F-box proteins belong to a multi-protein E3 ubiquitin ligase complex (SCF) that target proteins for degradation via the proteasome.We demonstrated that HAWAIIAN SKIRT(HWS), an Arabidopsis ubiquitin protein ligase (SCFHWS), regulates organ growth, flower development and timing of abscission. Mutants of this gene (hws-1) are pleiotropic and the most obvious phenotype is the fusion of its floral organs, a phenotype shared with the cuc1/cuc2 double mutants and over-expressing lines of MIR164B. To understand the molecular mechanisms of HWS during plant development, an ethylmethylsulphonate mutagenized population of hws-1 seeds was generated and screened for mutations suppressing the hws-1 sepal fusion. We isolated shs-1/hws-1, shs-2/hws-1, and shs-3/hws-1, (suppressor of hws-1) mutants. Mapping analyses shown that shs1 is mutated in the miRNA164 binding site of CUPSHAPED COTYLEDON1 (CUC1) mRNA; while shs-2 and shs-3 are novel alleles of the plant homolog of Exporting-5 HASTY (HST), known to be important in miRNA biogenesis, function and transport. Consequently, we renamed them cuc1-1D, hst23 and hst24, respectively. We demonstrated that transcript levels of CUC1 and CUPSHAPED COTYLEDON 2 (CUC2), and MIR164 change in cuc1-1D and in hws-1 mutants; analyses revealed a role for HWS in cell proliferation and control of floral organ number. Additional genetic crosses between hws-1 and mutant lines for genes in the miRNA pathway were performed and double mutants obtained shown restoration of the hws-1 sepal fusion phenotype. Our data propose HWS as a new regulator in miRNA pathway and reveal a role for HWS to control floral organ number and cell proliferation

HAWAIIAN SKIRT controls size and floral organ number by modulating CUC1 and CUC2 expression

The Arabidopsis thaliana F-box gene HAWAIIAN SKIRT (HWS) affects organ growth and the timing of floral organ abscission. The loss-of-function hws-1 mutant exhibits fused sepals and increased organ size. To understand the molecular mechanisms of HWS during plant development, we mutagenized hws-1 seeds with ethylmethylsulphonate (EMS) and screened for mutations suppressing hws-1 associated phenotypes. We isolated the shs1/hws-1 (suppressor of hws-1) mutant in which hws-1 sepal fusion phenotype was suppressed. The shs1/hws-1 mutant carries a G→A nucleotide substitution in the MIR164 binding site of CUP-SHAPED COTYLEDON 1 (CUC1) mRNA. CUC1 and CUP-SHAPED COTYLEDON 2 (CUC2) transcript levels were altered in shs1, renamed cuc1-1D, and in hws-1 mutant. Genetic interaction analyses using single, double and triple mutants of cuc1-1D, cuc2-1D (a CUC2 mutant similar to cuc1-1D), and hws-1, demonstrate that HWS, CUC1 and CUC2 act together to control floral organ number. Loss of function of HWS is associated with larger petal size due to alterations in cell proliferation and mitotic growth, a role shared with the CUC1 gene

A Plant Virus Movement Protein Regulates the Gcn2p Kinase in Budding Yeast

Virus life cycle heavily depends on their ability to command the host machinery in order to translate their genomes. Animal viruses have been shown to interfere with host translation machinery by expressing viral proteins that either maintain or inhibit eIF2α function by phosphorylation. However, this interference mechanism has not been described for any plant virus yet. Prunnus necrotic ringspot virus (PNRSV) is a serious pathogen of cultivated stone fruit trees. The movement protein (MP) of PNRSV is necessary for the cell-to-cell movement of the virus. By using a yeast-based approach we have found that over-expression of the PNRSV MP caused a severe growth defect in yeast cells. cDNA microarrays analysis carried out to characterise at the molecular level the growth interference phenotype reported the induction of genes related to amino acid deprivation suggesting that expression of MP activates the GCN pathway in yeast cells. Accordingly, PNRSV MP triggered activation of the Gcn2p kinase, as judged by increased eIF2α phosphorylation. Activation of Gcn2p by MP expression required a functional Tor1p kinase, since rapamycin treatment alleviated the yeast cell growth defect and blocked eIF2α phosphorylation triggered by MP expression. Overall, these findings uncover a previously uncharacterised function for PNRSV MP viral protein, and point out at Tor1p and Gcn2p kinases as candidate susceptibility factors for plant viral infections

An Antiviral Defense Role of AGO2 in Plants

Background: Argonaute (AGO) proteins bind to small-interfering (si)RNAs and micro (mi)RNAs to target RNA silencing against viruses, transgenes and in regulation of mRNAs. Plants encode multiple AGO proteins but, in Arabidopsis, only AGO1 is known to have an antiviral role. Methodology/Principal Findings: To uncover the roles of specific AGOs in limiting virus accumulation we inoculated turnip crinkle virus (TCV) to Arabidopsis plants that were mutant for each of the ten AGO genes. The viral symptoms on most of the plants were the same as on wild type plants although the ago2 mutants were markedly hyper-susceptible to this virus. ago2 plants were also hyper-susceptible to cucumber mosaic virus (CMV), confirming that the antiviral role of AGO2 is not specific to a single virus. For both viruses, this phenotype was associated with transient increase in virus accumulation. In wild type plants the AGO2 protein was induced by TCV and CMV infection. Conclusions/Significance: Based on these results we propose that there are multiple layers to RNA-mediated defense and counter-defense in the interactions between plants and their viruses. AGO1 represents a first layer. With some viruses, including TCV and CMV, this layer is overcome by viral suppressors of silencing that can target AGO1 and a second layer involving AGO2 limits virus accumulation. The second layer is activated when the first layer is suppressed because AGO2 is repressed by AGO1 via miR403. The activation of the second layer is therefore a direct consequence of the loss of the firs

Repression of FLOWERING LOCUS T Chromatin by Functionally Redundant Histone H3 Lysine 4 Demethylases in Arabidopsis

FLOWERING LOCUS T (FT) plays a key role as a mobile floral induction signal that initiates the floral transition. Therefore, precise control of FT expression is critical for the reproductive success of flowering plants. Coexistence of bivalent histone H3 lysine 27 trimethylation (H3K27me3) and H3K4me3 marks at the FT locus and the role of H3K27me3 as a strong FT repression mechanism in Arabidopsis have been reported. However, the role of an active mark, H3K4me3, in FT regulation has not been addressed, nor have the components affecting this mark been identified. Mutations in Arabidopsis thaliana Jumonji4 (AtJmj4) and EARLY FLOWERING6 (ELF6), two Arabidopsis genes encoding Jumonji (Jmj) family proteins, caused FT-dependent, additive early flowering correlated with increased expression of FT mRNA and increased H3K4me3 levels within FT chromatin. Purified recombinant AtJmj4 protein possesses specific demethylase activity for mono-, di-, and trimethylated H3K4. Tagged AtJmj4 and ELF6 proteins associate directly with the FT transcription initiation region, a region where the H3K4me3 levels were increased most significantly in the mutants. Thus, our study demonstrates the roles of AtJmj4 and ELF6 as H3K4 demethylases directly repressing FT chromatin and preventing precocious flowering in Arabidopsis