Terminal Region Research Articles

Characterization of a new barley greenbug resistance gene Rsg4 in the Chinese landrace CI 2458.

Barley (Hordeum vulgare) is a climate-resilient crop widely cultivated in both highly productive and suboptimal agricultural systems, and its ability to adapt to multiple biotic and abiotic stresses has contributed significantly to food security. Greenbug is a destructive insect pest for global barley production, and new greenbug resistance genes are needed to overcome the challenges posed by diverse greenbug biotypes in fields. CI 2458 is a Chinese landrace exhibiting a unique resistance profile to a set of 14 greenbug biotypes, which suggests the presence of a new greenbug resistance gene in CI 2458. A recombinant inbred line population from the cross Weskan × CI 2458 was developed, evaluated for responses to greenbug biotype F, and genotyped using single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing. Linkage analysis revealed a single gene, designated Rsg4, conditioning greenbug resistance in CI 2458. Rsg4 was delimited to a 1.14 Mb interval between SNP markers S3H_666512114 and S3H_667651446 in the terminal region of chromosome arm 3HL, with genetic distances of 1.2 cM proximal to S3H_667651446 and 1.1 cM distal to S3H_666512114. Allelism tests confirmed that Rsg4 is a new greenbug resistance gene independent of Rsg1 and Rsg3, which reside in the same chromosome arm. Rsg4 differs from Rsg1 alleles and Rsg3 in its resistance to greenbug biotype TX1, one of the most widely virulent biotypes. The introgression of Rsg4 into locally adapted barley cultivars is of agronomic importance, and kompetitive allele-specific polymerase chain reaction (KASP) markers flanking Rsg4, KASP-Rsg336-1 and KASP-Rsg336-2, enable rapid pyramiding of Rsg4 with other resistance genes to develop durable greenbug-resistant cultivars.

Self-association and multimer formation in AtLEA4-5, a desiccation-induced intrinsically disordered protein from plants.

During seed maturation, plants may experience severe desiccation, leading to the accumulation of late embryogenesis abundant (LEA) proteins. These intrinsically disordered proteins also accumulate in plant tissues under water deficit. Functional roles of LEA proteins have been proposed based on in vitro studies, where monomers are considered as the functional units. However, the potential formation of homo-oligomers has been little explored. In this work, we investigated the potential self-association of Arabidopsis thaliana group 4 LEA proteins (AtLEA4) using in vitro and in vivo approaches. LEA4 proteins represent a compelling case of study due to their high conservation throughout the plant kingdom. This protein family is characterized by a conserved N-terminal region, with a high alpha-helix propensity and invitro protective activity, as compared to the highly disordered and low-conserved C-terminal region. Our findings revealed that full-length AtLEA4 proteins oligomerize and that both terminal regions are sufficient for self-association in vitro. However, the ability of both amino and carboxy regions of AtLEA4-5 to self-associate invivo is significantly lower than that of the entire protein. Using high-resolution and quantitative fluorescence microscopy, we were able to disclose the unreported ability of LEA proteins to form high-order oligomers in planta. Additionally, we found that high-order complexes require the simultaneous engagement of both terminal regions, indicating that the entire protein is needed to attain such structural organization. This research provides valuable insights into the self-association of LEA proteins in plants and emphasizes the role of protein oligomer formation.

Developing a Reproducible Radiomics Model for Diagnosis of Active Crohn's Disease on CT Enterography Across Annotation Variations and Acquisition Differences.

To systematically identify radiomics features on CT enterography (CTE) scans which can accurately diagnose active Crohn's disease across multiple sources of variation. Retrospective study of CTE scans curated between 2013 and 2015, comprising 164 subjects (65 male, 99 female; all patients were over the age of 18) with endoscopic confirmation for the presence or absence of active Crohn's disease. All patients had three distinct sets of scans available (full and reduced dose, where the latter had been reconstructed via two different methods), acquired on a single scanner at a single institution. Radiomics descriptors from annotated terminal ileum regions were individually and systematically evaluated for resilience to different imaging variations (changes in dose/reconstruction, batch effects, and simulated annotation differences) via multiple reproducibility measures. Multiple radiomics models (by accounting for each source of variation) were evaluated in terms of classifier area under the ROC curve (AUC) for identifying patients with active Crohn's disease, across separate discovery and hold-out validation cohorts. Radiomics descriptors selected based on resiliency to multiple sources of imaging variation yielded the highest overall classification performance in the discovery cohort (AUC = 0.79 ± 0.04) which also best generalized in hold-out validation (AUC = 0.81). Performance was maintained across multiple doses and reconstructions while also being significantly better (p < 0.001) than non-resilient descriptors or descriptors only resilient to a single source of variation. Radiomics features can accurately diagnose active Crohn's disease on CTE scans across multiple sources of imaging variation via systematic analysis of reproducibility measures. Clinical utility and translatability of radiomics features for diagnosis and characterization of Crohn's disease on CTE scans will be contingent on their reproducibility across multiple types and sources of imaging variation.

Online Learning‐Based Event‐Triggered Model Predictive Control With Shrinking Prediction Horizon for Perturbed Nonlinear Systems

ABSTRACTThis article proposes an online learning‐based event‐triggered model predictive control (OLEMPC) scheme for constrained nonlinear systems with state‐dependent uncertainties. The scheme incorporates both the nominal and the learned models to ensure favorable theoretical properties during online learning. A composite measurement‐triggering strategy is devised to reduce the number of state measurements as well as solving the optimization problems. This strategy attenuates the conservatism in measurement and triggering through combining the event‐ and self‐triggering approaches. By implementing the algorithm, both state measurement and triggering frequency further decrease with the online refinement of the prediction model, and the prediction horizon adaptively shrinks as the state approaches the terminal region. It is shown that the feasibility of the optimization problem and stability of the closed‐loop system are guaranteed. Simulation results verify the effectiveness of this scheme in ensuring closed‐loop performance and alleviating computational burden.

Fluorescence in situ hybridization analysis of Oligonucleotide 5S rDNA, 45S rDNA, and (TTTAGGG)3 locations in Gloriosa superba L.

Gloriosa superba L. is a horticulturally and medicinally important plant native to Africa. However, the few cytogenetic studies of the species are mainly focused on chromosome counting and chromosome morphology-based karyotyping. Fluorescence in situ hybridization (FISH) is a powerful tool for the detection of DNA repetitive elements in a specific region of a chromosome. Here, detailed karyotypes of G. superba were constructed by FISH using 5S and 45S rDNAs, and telomeric repeat (TTTAGGG)3 oligonucleotides. Twenty-two chromosomes were observed. Two 5S rDNA hybridization signals were detected in the proximal regions of the short arms of one pair of chromosomes, which were adjacent to the (TTTAGGG)3 terminal signals. Four 45S rDNA signals were detected near the centromere region of the short arm of the four chromosomes, but one of these was very weak and almost undetectable compared to the others. Telomeric repeat hybridization signals were distributed at the terminal region of each chromosome. The chromosomes displayed were intact and the chromosome counts were accurate. Chromosome length ranged from 3.46 to 9.31 μm. These results will facilitate the cytogenetic mapping of other major repeats, thus contributing to an improved understanding of the G. superba genome structure and evolutionary history.

Rheology and aging of amine functionalized polyolefins

The time dependent rheo-mechanical properties of a class of associating polymers (amine-functionalized polyolefins) are investigated using rheology, differential scanning calorimetry (DSC), infrared microscopy, and small-angle x-ray scattering (SAXS) measurement. The modulus of the sample increases with time and temperature as determined by shear rheology. With higher temperature and longer equilibration time, there is a gradual decrease in the power-law scaling of storage and loss moduli in the terminal flow region and the emergence of an additional low-frequency plateau in the storage modulus. The aging behavior at different temperatures is found to be correlated with the horizontal shift factors obtained from the time-temperature superposition. With increasing aging time, there is an increase in the glass transition temperatures (DSC), and a continuous red shift in the associated amine stretching peak (Fourier-transform infrared). SAXS also shows the emergence of a dominant microstructure after aging of the sample for a long time. Based on the characterization results, an underlying microscopic origin of the aging process is proposed.

Crystal Structure and Molecular Mechanism of Isocitrate Lyase from Chloroflexus aurantiacus.

Chloroflexus aurantiacus is a green, nonsulfur bacterium that employs the 3-hydroxypropionate cycle to grow, using carbon dioxide/bicarbonate as its primary carbon source. Like most bacteria, it possesses the glyoxylate cycle, facilitated by malate synthase and isocitrate lyase (ICL), allowing a "tricarboxylic acid cycle" bypass. C. aurantiacus also harbors ICL, an enzyme that catalyzes reversible isocitrate cleavage into glyoxylate and succinate. This study presents the crystal structures of C. aurantiacus-derived ICL (CaICL), in its Mg2+-bound and Mn2+ and isocitrate-bound forms, elucidating its substrate-binding mechanism and catalytic loop dynamics. CaICL forms a homotetramer and interacts with isocitrate via critical active-site residues, revealing its catalytic mechanism. The stabilization of the catalytic loop and adjacent terminal regions upon isocitrate binding underscores its functional significance. These findings advance our understanding regarding ICL enzymes, offering a basis for future investigations into their biological roles and potential applications.

Insight into the structure-activity relationship of thermal hysteresis activity of cod collagen peptides through peptidomics and bioinformatics approaches

To elucidate the correlation between variations in thermal hysteresis activity (THA) and the physicochemical properties and structure, antifreeze peptides (AFPs) of isolated fractions (CCP-1 and CCP-2) were characterized on based peptidomics and bioinformatics. The results revealed a positive correlation between the THA of cod collagen antifreeze peptide (CCAFP) and peptide chain length, isoelectric point, and hydrophobic amino acid content. Notably, the THA of CCP-1, which has higher alkaline amino acid content, was 2.60 °C at a concentration of 10 mg/mL, significantly higher than CCP (1.90 °C) and CCP-2 (2.27 °C). Glycine, proline, and valine were the vital amino acids to the formation of hydrogen bonds. Conversely, aspartic and glutamic acids at terminal regions of AFPs tended to introduce kinks in their structures. This distortion reduced binding sites for ice crystals, thereby decreasing their THA, providing a theory for understanding the physicochemical properties and structure of AFPs that influence their THA.

A theoretical study on symmetrical non-fullerene electron acceptors molecules on BDTPT based derivatives to enhance photovoltaic properties of organic solar cells

An innovative and promising approach to developing sustainable energy solutions and promoting an eco-friendly society is the use of organic solar cells. The key component for a solution-processed bulk-heterojunction organic solar cell is the photoactive layer’s embedded donor and acceptor components. This research presents seven modified molecules comprising the A–D–A type structural configuration, entitled A1–A7. All these designed moieties exhibit marvelous outcomes in optoelectronic features, including λmax and band gap, owing to non-fullerene acceptors in the terminal regions. All these compounds are computationally assessed by employing B3LYP at 6-31G (d,p) basis set using chloroform solvent. Compared to the reference molecule, the designed molecules (A1, A2, A4, A5, A6, A7) have reflected breakthrough results. The prerequisite for directing the practical application of designed acceptors is the efficient charge transfer, evidenced by coupling the J61 donor complex with the designed A5 acceptor.

The remarkable microquasar S26: A super-Eddington PeVatron

S26 is an extragalactic microquasar with the most powerful jets ever discovered. They have a kinetic luminosity of $L_ j $. This implies that the accretion power to the black hole should be super-Eddington, of the order of $L_ acc j $. However, the observed X-ray flux of this system indicates an apparent very sub-Eddington accretion luminosity of $L_ X We aim to characterize the nature of S26, explain the system emission, and study the feasibility of super-Eddington microquasars as potential PeVatron sources. We first analyze multi-epoch X-ray observations of S26 obtained with XMM-Newton and model the super-Eddington disk and its wind. We then develop a jet model and study the particle acceleration and radiative processes that occur in shocks generated near the base of the jet and in its terminal region. We find that the discrepancy between the jet and the apparent disk luminosities in S26 is caused by the complete absorption of the disk radiation by the wind ejected from the super-Eddington disk. The non-thermal X-rays are produced near the base of the jet, and the thermal X-rays are emitted in the terminal regions. The radio emission observed with the Australia Telescope Compact Array can be explained as synchrotron radiation produced at the reverse shock in the lobes. We also find that S26 can accelerate protons to PeV energies in both the inner jet and the lobes. The ultra-high energy protons accelerated in the lobes of S26 are injected into the interstellar medium with a total power of $ We conclude that S26 is a super-Eddington microquasar with a dense disk-driven wind that obscures the X-ray emission from the inner disk, and that the supercritical nature of the system allows the acceleration of cosmic rays to PeV energies.

Effect of Phase Structure on the Viscoelasticity and Mechanical Properties of Isotactic Polypropylene Multicomponents Polymerized with Non-Conjugated α,ω-Diene.

Increasing of rubber content in isotactic polypropylene/ethylene-propylene rubber (iPP/EPR) alloys can extend the applications of this kind of polyolefin. The EPR content and phase structure of isotactic polypropylene multicomponents have great effect on the viscoelasticity and mechanical properties. iPP/EPR in-reactor alloys with a high EPR content were obtained through the in situ crosslinking of EPR chains with α,ω-diene. The morphological observation results indicate that the crosslinked iPP/EPR in-reactor alloys have a good spherical shape with clean and rough external surfaces. The high EPR content is finely dispersed in the crosslinked iPP/EPR alloys in areas ranging in size from tens of nanometers to several micrometers, which implies that a sufficient crosslinking degree of EPR chains can effectively prevent their aggregation and restrict macro-phase separation. The rheological results show a clear plateau in the terminal region, which reveals an entangled polymer chain network in the crosslinked iPP/EPR alloys. The well-dispersed EPR and the bi-continuous phase structure have a great effect on the mechanical properties of the isotactic polypropylene multicomponent which were assessed.

OligoFormer: an accurate and robust prediction method for siRNA design.

RNA interference (RNAi) has become a widely used experimental approach for post-transcriptional regulation and is increasingly showing its potential as future targeted drugs. However, the prediction of highly efficient siRNAs (small interfering RNAs) is still hindered by dataset biases, the inadequacy of prediction methods, and the presence of off-target effects. To overcome these limitations, we propose an accurate and robust prediction method, OligoFormer, for siRNA design. OligoFormer comprises three different modules including thermodynamic calculation, RNA-FM module, and Oligo encoder. Oligo encoder is the core module based on the transformer encoder. Taking siRNA and mRNA sequences as input, OligoFormer can obtain thermodynamic parameters, RNA-FM embedding, and Oligo embedding through these three modules, respectively. We carefully benchmarked OligoFormer against six comparable methods on siRNA efficacy datasets. OligoFormer outperforms all the other methods, with an average improvement of 9% in AUC, 6.6% in PRC, 9.8% in F1 score, and 5.1% in PCC compared to the best method among them in our inter-dataset validation. We also provide a comprehensive pipeline with prediction of siRNA efficacy and off-target effects using PITA score and TargetScan score. The ablation study shows RNA-FM module and thermodynamic parameters improved the performance and accelerated convergence of OligoFormer. The saliency maps by gradient backpropagation and base preference maps show certain base preferences in initial and terminal region of siRNAs. The source code of OligoFormer is freely available on GitHub at: https://github.com/lulab/OligoFormer. Docker image of OligoFormer is freely available on the docker hub at https://hub.docker.com/r/yilanbai/oligoformer.

First Karyotype Description for Acanthognathus rudis Brown &amp; Kempf, 1969 (Formicidae: Myrmicinae) with Notes on Its Natural History

The trap-jaw ant Acanthognathus Mayr (Myrmicinae: Dacetina) has been subject of various studies since 1969, but there has been no progress in its cytogenetics. This study describes provides the first karyotype description of a representative of the genus, A. rudis, including chromosomal number, morphology, and the distribution of repetitive sequences. A colony collected in Southeastern Brazil exhibited a diploid number of 2n = 14 (12 metacentrics + 2 submetacentrics), the lowest number among the Daceton genus-group and the first Neotropical representative of this group to be karyologically studied. The rDNA clusters were located in the pericentromeric region of a single chromosome pair, (GA)n blocks were present only in the terminal regions of both chromosome arms in the euchromatic regions, and (TTAGG)n hybridized with the telomeres of all chromosomes, without interstitial telomeric sites. The repetitive sequence patterns align with those observed in other Neotropical Formicidae. Additionally, we documented new behavioral aspects of mandible use in A. rudis workers and provided the first images of its immature stages. These findings emphasize the need for further research on Acanthognathus and the other Daceton genus-group.

Translation of Overlapping Open Reading Frames Promoted by Type 2 IRESs in Avian Calicivirus Genomes.

Caliciviruses have positive-sense RNA genomes, typically with short 5'-untranslated regions (5'UTRs) that precede the long open reading frame 1 (ORF1). Exceptionally, some avian caliciviruses have long 5'UTRs containing a picornavirus-like internal ribosomal entry site (IRES), which was likely acquired by horizontal gene transfer. Here, we identified numerous additional avian calicivirus genomes with IRESs, predominantly type 2, and determined that many of these genomes contain a ~200-300 codon-long ORF (designated ORF1*) that overlaps the 5'-terminal region of ORF1. The activity of representative type 2 IRESs from grey teal calicivirus (GTCV) and Caliciviridae sp. isolate yc-13 (RaCV1) was confirmed by in vitro translation. Toeprinting showed that in cell-free extracts and in vitro reconstituted reactions, ribosomal initiation complexes assembled on the ORF1* initiation codon and at one or two AUG codons in ORF1 at the 3'-border and/or downstream of the IRES. Initiation at all three sites required eIF4A and eIF4G, which bound to a conserved region of the IRES; initiation on the ORF1* and principal ORF1 initiation codons involved eIF1/eIF1A-dependent scanning from the IRES's 3'-border. Initiation on these IRESs was enhanced by the IRES trans-acting factors (ITAFs) Ebp1/ITAF45, which bound to the apical subdomain Id of the IRES, and PTB (GTCV) or PCBP2 (RaCV1).

Adaptive Transmission Interval-Based Self-Triggered Model Predictive Control for Autonomous Underwater Vehicles with Additional Disturbances

Most existing model predictive control (MPC) methods overlook the network resource limitations of autonomous underwater vehicles (AUVs), limiting their applicability in real systems. This article addresses this gap by introducing an adaptive transmission, interval-based, and self-triggered model predictive control for AUVs operating under ocean disturbances. This approach enhances system stability while reducing resource consumption by optimizing MPC update frequencies and communication resource usage. Firstly, the method evaluates the discrepancy between system states at sampling instants and their optimal predictions. This significantly reduces the conservatism in the state-tracking errors caused by ocean disturbances compared to traditional approaches. Secondly, a self-triggering mechanism was employed, limiting information exchange to specified triggering instants to conserve communication resources more effectively. Lastly, by designing a robust terminal region and optimizing parameters, the recursive feasibility of the optimization problem is ensured, thereby maintaining the stability of the closed-loop system. The simulation results illustrate the efficacy of the controller.

The GC% landscape of the Nucleocytoviricota.

Genomic studies on sequence composition employ various approaches, such as calculating the proportion of guanine and cytosine within a given sequence (GC% content), which can shed light on various aspects of the organism's biology. In this context, GC% can provide insights into virus-host relationships and evolution. Here, we present a comprehensive gene-by-gene analysis of 61 representatives belonging to the phylum Nucleocytoviricota, which comprises viruses with the largest genomes known in the virosphere. Parameters were evaluated not only based on the average GC% of a given viral species compared to the entire phylum but also considering gene position and phylogenetic history. Our results reveal that while some families exhibit similar GC% among their representatives (e.g., Marseilleviridae), others such as Poxviridae, Phycodnaviridae, and Mimiviridae have members with discrepant GC% values, likely reflecting adaptation to specific biological cycles and hosts. Interestingly, certain genes located at terminal regions or within specific genomic clusters show GC% values distinct from the average, suggesting recent acquisition or unique evolutionary pressures. Horizontal gene transfer and the presence of potential paralogs were also assessed in genes with the most discrepant GC% values, indicating multiple evolutionary histories. Taken together, to the best of our knowledge, this study represents the first global and gene-by-gene analysis of GC% distribution and profiles within genomes of Nucleocytoviricota members, highlighting their diversity and identifying potential new targets for future studies.

Cellular RNA-binding proteins LARP4 and PABPC1 synergistically facilitate viral translation of coronavirus PEDV

Coronaviruses are causing epizootic diseases and thus are a substantial threat for both domestic and wild animals. These viruses depend on the host translation machinery to complete their life cycle. The current paper identified cellular RNA-binding proteins (RBPs), La-related protein 4 (LARP4) and polyadenylate-binding protein cytoplasmic 1 (PABPC1), as critical regulators of efficient translation of the coronavirus porcine epidemic diarrhea virus (PEDV) mRNA. In Vero cells, PEDV infection caused LARP4 to migrate from the nucleus to the cytoplasm in a chromosome region maintenance1 (CRM1)-independent pathway. In the absence of the nuclear export signal of LARP4, viral translation was not promoted by LARP4. A further study unveiled that the cytoplasmic LARP4 binds to the 3′-terminal untranslated region (3′UTR) of PEDV mRNA with the assistance of PABPC1 to facilitate viral translation. LARP4 knockdown reduced the promotion of the PABPC1-induced 3′UTR translation activity. Moreover, the rabbit reticulocyte lysate (RRL) system revealed that the prokaryotic expressed protein LARP4 and PABPC1 enhance PEDV mRNA translation. To our knowledge, this is the first study demonstrating that PEDV induces nucleo-cytoplasmic shuttling of LARP4 to enhance its own replication, which broadens our insights into how viruses use host's RBPs for the efficient translation of viral mRNA.

Chromosomal Characterization of Five Medicinally Significant Phyllanthus Species in Bangladesh by DNA Base-Specific Fluorochrome Banding Technique

ABSTRACT Five Phyllanthus species were characterized using a fluorochrome chromosome banding technique with CMA and DAPI. This genus displayed a range of somatic chromosomal counts, including 2n = 2x = 26 (diploid) in P. acidus, P. niruri, and P. reticulatus; 2n = 6x = 48 (hexaploid) in P. urinaria; and 2n = 10x = 100 (decaploid) in P. emblica (wild and cultivated varieties), which exhibited a multi-basic chromosome number. The centromeric and terminal regions of the chromosomes contained most of the CMA and DAPI bands, indicating that GC- and AT-rich repeats had accumulated in these locations. The diversity based on the heterochromatin distribution patterns made it possible to use the CMA and DAPI banding approaches to analyze and characterize these five Phyllanthus species.

Assessing a respiratory toxic infectious bronchitis virus (IBV) strain: isolation, identification, pathogenicity, and immunological failure insights.

Infectious bronchitis virus (IBV) is caused by avian coronavirus and poses a global economic threat to the poultry industry. In 2023, a highly pathogenic IBV strain, IBV/CN/GD20230501, was isolated and identified from chickens vaccinated with IBV-M41 in Guangdong, China. This study comprehensively investigated the biological characteristics of the isolated IBV strain, including its genotype, whole genome sequence analysis of its S1 gene, pathogenicity, host immune response, and serum non-targeted metabolomics. Through the analysis of the S1 gene sequence, serum neutralization tests, and comparative genomics, it was proven that IBV/CN/GD20230501 belongs to the GI-I type of strain and is serotype II. One alanine residue in the S1 subunit of the isolated strain was mutated into serine, and some mutations were observed in the ORF1ab gene and the terminal region of the genome. Animal challenge experiments using the EID50 and TCID50 calculations showed that IBV/CN/GD20230501 possesses strong respiratory pathogenicity, with early and long-term shedding of viruses and rapid viral spread. Antibody detection indicated that chickens infected with IBV/CN/GD20230501 exhibited delayed expression of early innate immune genes, while those infected with M41 showed rapid gene induction and effective viral control. Metabolomics analysis demonstrated that this virus infection led to differential expression of 291 ions in chicken serum, mainly affecting the citric acid cycle (tricarboxylic acid cycle).IMPORTANCEThis study identified an infectious bronchitis virus (IBV) strain isolated from vaccinated chickens in an immunized population that had certain sequence differences compared to IBV-M41, resulting in significantly enhanced pathogenicity and host defense. This strain has the potential to replace M41 as a more suitable challenge model for drug research. The non-targeted metabolomics analysis highlighting the citric acid cycle provides a new avenue for studying this highly virulent strain.

MEIKIN expression and its C-terminal phosphorylation by PLK1 is closely related the metaphase-anaphase transition by affecting cyclinB1 and Securin stabilization in meiotic oocyte.

Oocyte meiotic maturation failure and chromosome abnormality is one of the main causes of infertility, abortion, and diseases. The mono-orientation of sister chromatids during the first meiosis is important for ensuring accurate chromosome segregation in oocytes. MEIKIN is a germ cell-specific protein that can regulate the mono-orientation of sister chromatids and the protection of the centromeric cohesin complex during meiosisI. Here we found that MEIKIN is a maternal protein that was highly expressed in mouse oocytes before the metaphaseI (MI) stage, but became degraded by the MII stage and dramatically reduced after fertilization. Strikingly, MEIKIN underwent phosphorylation modification after germinal vesicle breakdown (GVBD), indicating its possible function in subsequent cellular event regulation. We further showed that MEIKIN phosphorylation was mediated by PLK1 at its carboxyl terminal region and its C-terminus was its key functional domain. To clarify the biological significance of meikin degradation during later stages of oocyte maturation, exogenous expression of MEIKIN was employed, which showed that suppression of MEIKIN degradation resulted in chromosome misalignment, cyclinB1 and Securin degradation failure, and MI arrest through a spindle assembly checkpoint (SAC)-independent mechanism. Exogenous expression of MEIKIN also inhibited metaphaseII (MII) exit and early embryo development. These results indicate that proper MEIKIN expression level and its C-terminal phosphorylation by PLK1 are critical for regulating the metaphase-anaphase transition in meiotic oocyte. The findings of this study are important for understanding the regulation of chromosome segregation and the prevention meiotic abnormality.