scholarly journals The cohesin release factor Wapl interacts with Bub3 to govern SAC activity in female meiosis I

2020 ◽  
Vol 6 (15) ◽  
pp. eaax3969
Author(s):  
Changyin Zhou ◽  
Yilong Miao ◽  
Zhaokang Cui ◽  
Xiayan ShiYang ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Mass Spectrometry Analysis ◽  
Female Meiosis ◽  
Spectrometry Analysis ◽  
Binding Partner ◽  
Meiotic Progression ◽  
Cohesin Subunit ◽  
Normal Meiosis ◽  
Meiosis I

During mitotic prophase, cohesins are removed from chromosome arms by Wapl to ensure faithful sister chromatid separation. However, during female meiosis I, the resolution of chiasmata requires the proteolytic cleavage of cohesin subunit Rec8 along chromosome arms by Separase to separate homologs, and thus the role of Wapl remained unknown. Here, we report that Wapl functions as a regulator of spindle assembly checkpoint (SAC) to prevent aneuploidy in meiosis I. Depletion of Wapl accelerates meiotic progression, inactivates SAC, and causes meiotic defects such as aberrant spindle/chromosome structure and incorrect kinetochore-microtubule (K-MT) attachment, consequently leading to aneuploid eggs. Notably, we identify Bub3 as a binding partner of Wapl by immunoprecipitation and mass spectrometry analysis. We further determine that Wapl controls the SAC activity by maintaining Bub3 protein level and document that exogenous Bub3 restores the normal meiosis in Wapl-depleted oocytes. Together, our findings uncover unique, noncanonical roles for Wapl in mediating control of the SAC in female meiosis I.

scholarly journals Dual-mode regulation of the APC/C by CDK1 and MAPK controls meiosis I progression and fidelity

2014 ◽  
Vol 204 (6) ◽  
pp. 891-900 ◽  
Author(s):  
Ibtissem Nabti ◽  
Petros Marangos ◽  
Jenny Bormann ◽  
Nobuaki R. Kudo ◽  
John Carroll
Keyword(s):  
Protein Kinase ◽  
Spindle Assembly Checkpoint ◽  
Mitogen Activated Protein Kinase ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
Female Meiosis ◽  
Dual Mode ◽  
Mitogen Activated Protein ◽  
Meiosis I

Female meiosis is driven by the activities of two major kinases, cyclin-dependent kinase 1 (Cdk1) and mitogen-activated protein kinase (MAPK). To date, the role of MAPK in control of meiosis is thought to be restricted to maintaining metaphase II arrest through stabilizing Cdk1 activity. In this paper, we find that MAPK and Cdk1 play compensatory roles to suppress the anaphase-promoting complex/cyclosome (APC/C) activity early in prometaphase, thereby allowing accumulation of APC/C substrates essential for meiosis I. Furthermore, inhibition of MAPK around the onset of APC/C activity at the transition from meiosis I to meiosis II led to accelerated completion of meiosis I and an increase in aneuploidy at metaphase II. These effects appear to be mediated via a Cdk1/MAPK-dependent stabilization of the spindle assembly checkpoint, which when inhibited leads to increased APC/C activity. These findings demonstrate new roles for MAPK in the regulation of meiosis in mammalian oocytes.

scholarly journals Echinoderm Microtubule Associated Protein Like 1 Is Indispensable for Oocyte Spindle Assembly and Meiotic Progression in Mice

2021 ◽  
Vol 9 ◽  
Author(s):  
Hong Yin ◽  
Teng Zhang ◽  
Hao Wang ◽  
Xin Hu ◽  
Xuan Hou ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Polar Body ◽  
Spindle Assembly ◽  
Mass Spectrometry Analysis ◽  
Spectrometry Analysis ◽  
Meiotic Progression ◽  
Spindle Poles ◽  
First Polar Body ◽  
Specific Localization ◽  
Oocyte Meiotic Maturation

Completion of the first meiosis is an essential prerequisite for producing a functionally normal egg for fertilization and embryogenesis, but the precise mechanisms governing oocyte meiotic progression remains largely unclear. Here, we report that echinoderm microtubule associated protein (EMAP) like 1 (EML1), a member of the conserved EMAP family proteins, plays a crucial role in the control of oocyte meiotic progression in the mouse. Female mice carrying an ENU-induced nonsense mutation (c.1956T > A; p.Tyr652∗) of Eml1 are infertile, and the majority of their ovulated oocytes contain abnormal spindles and misaligned chromosomes. In accordance with the mutant oocyte phenotype, we find that EML1 is colocalized with spindle microtubules during the process of normal oocyte meiotic maturation, and knockdown (KD) of EML1 by specific morpholinos in the fully grown oocytes (FGOs) disrupts the integrity of spindles, and delays meiotic progression. Moreover, EML1-KD oocytes fail to progress to metaphase II (MII) stage after extrusion of the first polar body, but enter into interphase and form a pronucleus containing decondensed chromatins. Further analysis shows that EML1-KD impairs the recruitment of γ-tubulin and pericentrin to the spindle poles, as well as the attachment of kinetochores to microtubules and the proper inactivation of spindle assembly checkpoint at metaphase I (MI). The loss of EML1 also compromises the activation of maturation promoting factor around the time of oocyte resumption and completion of the first meiosis, which, when corrected by WEE1/2 inhibitor PD166285, efficiently rescues the phenotype of oocyte delay of meiotic resumption and inability of reaching MII. Through IP- mass spectrometry analysis, we identified that EML1 interacts with nuclear distribution gene C (NUDC), a critical mitotic regulator in somatic cells, and EML1-KD disrupts the specific localization of NUDC at oocyte spindles. Taken together, these data suggest that EML1 regulates acentrosomal spindle formation and the progression of meiosis to MII in mammalian oocytes, which is likely mediated by distinct mechanisms.

scholarly journals Shared Components of the FRQ-Less Oscillator and TOR Pathway Maintain Rhythmicity in Neurospora

2021 ◽  
pp. 074873042199994
Author(s):  
Rosa Eskandari ◽  
Lalanthi Ratnayake ◽  
Patricia L. Lakin-Thomas
Keyword(s):  
Circadian Rhythms ◽  
Clock Genes ◽  
Nutrient Sensing ◽  
Mass Spectrometry Analysis ◽  
Growth Responses ◽  
Tor Pathway ◽  
Spectrometry Analysis ◽  
Binding Partner ◽  
Binding Partners ◽  
Free Running

Molecular models for the endogenous oscillators that drive circadian rhythms in eukaryotes center on rhythmic transcription/translation of a small number of “clock genes.” Although substantial evidence supports the concept that negative and positive transcription/translation feedback loops (TTFLs) are responsible for regulating the expression of these clock genes, certain rhythms in the filamentous fungus Neurospora crassa continue even when clock genes ( frq, wc-1, and wc-2) are not rhythmically expressed. Identification of the rhythmic processes operating outside of the TTFL has been a major unresolved area in circadian biology. Our lab previously identified a mutation ( vta) that abolishes FRQ-less rhythmicity of the conidiation rhythm and also affects rhythmicity when FRQ is functional. Further studies identified the vta gene product as a component of the TOR (Target of Rapamycin) nutrient-sensing pathway that is conserved in eukaryotes. We now report the discovery of TOR pathway components including GTR2 (homologous to the yeast protein Gtr2, and RAG C/D in mammals) as binding partners of VTA through co-immunoprecipitation (IP) and mass spectrometry analysis using a VTA-FLAG strain. Reciprocal IP with GTR2-FLAG found VTA as a binding partner. A Δ gtr2 strain was deficient in growth responses to amino acids. Free-running conidiation rhythms in a FRQ-less strain were abolished in Δ gtr2. Entrainment of a FRQ-less strain to cycles of heat pulses demonstrated that Δ gtr2 is defective in entrainment. In all of these assays, Δ gtr2 is similar to Δ vta. In addition, expression of GTR2 protein was found to be rhythmic across two circadian cycles, and functional VTA was required for GTR2 rhythmicity. FRQ protein exhibited the expected rhythm in the presence of GTR2 but the rhythmic level of FRQ dampened in the absence of GTR2. These results establish association of VTA with GTR2, and their role in maintaining functional circadian rhythms through the TOR pathway.

scholarly journals Structural Characterization of Act c 10.0101 and Pun g 1.0101—Allergens from the Non-Specific Lipid Transfer Protein Family

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 256
Author(s):  
Andrea O’Malley ◽  
Swanandi Pote ◽  
Ivana Giangrieco ◽  
Lisa Tuppo ◽  
Anna Gawlicka-Chruszcz ◽  
...  
Keyword(s):  
Immunoglobulin E ◽  
Lipid Transfer Protein ◽  
Mass Spectrometry Analysis ◽  
Lipid Transfer ◽  
Helical Structures ◽  
Spectrometry Analysis ◽  
X Ray Crystallography ◽  
Transfer Protein ◽  
Specific Lipid

(1) Background: Non-specific lipid transfer proteins (nsLTPs), which belong to the prolamin superfamily, are potent allergens. While the biological role of LTPs is still not well understood, it is known that these proteins bind lipids. Allergen nsLTPs are characterized by significant stability and resistance to digestion. (2) Methods: nsLTPs from gold kiwifruit (Act c 10.0101) and pomegranate (Pun g 1.0101) were isolated from their natural sources and structurally characterized using X-ray crystallography (3) Results: Both proteins crystallized and their crystal structures were determined. The proteins have a very similar overall fold with characteristic compact, mainly α-helical structures. The C-terminal sequence of Act c 10.0101 was updated based on our structural and mass spectrometry analysis. Information on proteins’ sequences and structures was used to estimate the risk of cross-reactive reactions between Act c 10.0101 or Pun g 1.0101 and other allergens from this family of proteins. (4) Conclusions: Structural studies indicate a conformational flexibility of allergens from the nsLTP family and suggest that immunoglobulin E binding to some surface regions of these allergens may depend on ligand binding. Both Act c 10.0101 and Pun g 1.0101 are likely to be involved in cross-reactive reactions involving other proteins from the nsLTP family.

scholarly journals The Olsenella Uli Induced Pneumonia: A Case Report

2021 ◽  
Author(s):  
Yufen Yan ◽  
Hong Li ◽  
Shuai Li ◽  
Shuhui Liu ◽  
Nan Jia ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Pulmonary Infection ◽  
Mass Spectrometry Analysis ◽  
Causative Role ◽  
Positive Bacterium ◽  
Spectrometry Analysis ◽  
First Case ◽  
Infection Treatment ◽  
Third Generation Cephalosporins

Abstract Olsenella uli is a Gram-positive bacterium common in the oral cavity or gastrointestinal tract. Here we reported a first case of human pneumonia caused by the Olsenella uli. The identification of Olsenella uli was based on micromorphology, sequence analysis and mass spectrometry analysis of the bacteria recovered from sputum. Ceftazidime，one of the third generation cephalosporins was used for the anti-infection treatment of the patient. CT results showed a significant improvement of the pulmonary lesion and pleural effusion and recovery from pulmonary infection after 10 days. The mechanism underlying Olsenella uli induced pneumonia is unclear, our report suggests a causative role of gingival bacteria in pathogenesis of pneumonia, and the intervention by Ceftazidime may offer a therapeutic strategy for Olsenella uli infection.

Quantitative proteomics identifies FOLR1 to drive sorafenib resistance via activating autophagy in hepatocellular carcinoma cells

2021 ◽  
Author(s):  
Hongwei Chu ◽  
Changqing Wu ◽  
Qun Zhao ◽  
Rui Sun ◽  
Kuo Yang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Folate Receptor ◽  
Mass Spectrometry Analysis ◽  
Label Free ◽  
Spectrometry Analysis ◽  
Underlying Mechanisms ◽  
Related Proteins ◽  
Hcc Cells

Abstract Sorafenib is commonly used to treat advanced human hepatocellular carcinoma (HCC). However, clinical efficacy has been limited by drug resistance. In this study, we used label-free quantitative proteomic analysis to systematically investigate the underlying mechanisms of sorafenib resistance in HCC cells. A total of 1709 proteins were confidently quantified. Among them, 89 were differentially expressed, and highly enriched in the processes of cell-cell adhesion, negative regulation of apoptosis, response to drug and metabolic processes involving in sorafenib resistance. Notably, folate receptor α (FOLR1) was found to be significantly upregulated in resistant HCC cells. In addition, in-vitro studies showed that overexpression of FOLR1 decreased the sensitivity of HCC cells to sorafenib, whereas siRNA-directed knockdown of FOLR1 increased the sensitivity of HCC cells to sorafenib. Immunoprecipitation-mass spectrometry analysis suggested a strong link between FOLR1 and autophagy related proteins. Further biological experiments found that FOLR1-related sorafenib resistance was accompanied by the activation of autophagy, whereas inhibition of autophagy significantly reduced FOLR1-induced cell resistance. These results suggest the driving role of FOLR1 in HCC resistance to sorafenib, which may be exerted through FOLR1-induced autophagy. Therefore, this study may provide new insights into understanding the mechanism of sorafenib resistance.

scholarly journals The Mouse Polyubiquitin Gene Ubb Is Essential for Meiotic Progression

2007 ◽  
Vol 28 (3) ◽  
pp. 1136-1146 ◽  
Author(s):  
Kwon-Yul Ryu ◽  
Shamim A. Sinnar ◽  
Laura G. Reinholdt ◽  
Sergio Vaccari ◽  
Susan Hall ◽  
...  
Keyword(s):  
Germ Cells ◽  
Striking Similarity ◽  
Eukaryotic Evolution ◽  
Targeted Disruption ◽  
Male And Female ◽  
Meiotic Progression ◽  
Polyubiquitin Gene ◽  
Polyubiquitin Genes ◽  
Meiosis I

ABSTRACT Ubiquitin is encoded in mice by two polyubiquitin genes, Ubb and Ubc, that are considered to be stress inducible and two constitutively expressed monoubiquitin (Uba) genes. Here we report that targeted disruption of Ubb results in male and female infertility due to failure of germ cells to progress through meiosis I and hypogonadism. In the absence of Ubb, spermatocytes and oocytes arrest during meiotic prophase, before metaphase of the first meiotic division. Although cellular ubiquitin levels are believed to be maintained by a combination of functional redundancy among the four ubiquitin genes, stress inducibility of the two polyubiquitin genes, and ubiquitin recycling by proteasome-associated isopeptidases, our results indicate that ubiquitin is required for and consumed during meiotic progression. The striking similarity of the meiotic phenotype in Ubb −/− germ cells to the sporulation defect in fission yeast (Schizosaccharomyces pombe) lacking a polyubiquitin gene suggests that a meiotic role of the polyubiquitin gene has been conserved throughout eukaryotic evolution.

scholarly journals Dissection of the Role of Pili and Type 2 and 3 Secretion Systems in Adherence and Biofilm Formation of an Atypical Enteropathogenic Escherichia coli Strain

2013 ◽  
Vol 81 (10) ◽  
pp. 3793-3802 ◽  
Author(s):  
Rodrigo T. Hernandes ◽  
Miguel A. De la Cruz ◽  
Denise Yamamoto ◽  
Jorge A. Girón ◽  
Tânia A. T. Gomes
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Coli Strain ◽  
Mass Spectrometry Analysis ◽  
Secretion Systems ◽  
Content Type ◽  
Spectrometry Analysis ◽  
Rigid Rod

ABSTRACTAtypical enteropathogenicEscherichia coli(aEPEC) strains are diarrheal pathogens that lack bundle-forming pilus production but possess the virulence-associated locus of enterocyte effacement. aEPEC strain 1551-2 produces localized adherence (LA) on HeLa cells; however, its isogenic intimin (eae) mutant produces a diffuse-adherence (DA) pattern. In this study, we aimed to identify the DA-associated adhesin of the 1551-2eaemutant. Electron microscopy of 1551-2 identified rigid rod-like pili composed of an 18-kDa protein, which was identified as the major pilin subunit of type 1 pilus (T1P) by mass spectrometry analysis. Deletion offimAin 1551-2 affected biofilm formation but had no effect on adherence properties. Analysis of secreted proteins in supernatants of this strain identified a 150-kDa protein corresponding to SslE, a type 2 secreted protein that was recently reported to be involved in biofilm formation of rabbit and human EPEC strains. However, neither adherence nor biofilm formation was affected in a 1551-2sslEmutant. We then investigated the role of the EspA filament associated with the type 3 secretion system (T3SS) in DA by generating a doubleeae espAmutant. This strain was no longer adherent, strongly suggesting that the T3SS translocon is the DA adhesin. In agreement with these results, specific anti-EspA antibodies blocked adherence of the 1551-2eaemutant. Our data support a role for intimin in LA, for the T3SS translocon in DA, and for T1P in biofilm formation, all of which may act in concert to facilitate host intestinal colonization by aEPEC strains.

scholarly journals Regulation of the meiotic divisions of mammalian oocytes and eggs

2018 ◽  
Vol 46 (4) ◽  
pp. 797-806 ◽  
Author(s):  
Jessica R. Sanders ◽  
Keith T. Jones
Keyword(s):  
Cell Division ◽  
Luteinizing Hormone ◽  
Spindle Assembly Checkpoint ◽  
Asymmetric Cell Division ◽  
Homologous Chromosomes ◽  
Mammalian Oocyte ◽  
Cellular Events ◽  
The Hours ◽  
Meiosis I

Initiated by luteinizing hormone and finalized by the fertilizing sperm, the mammalian oocyte completes its two meiotic divisions. The first division occurs in the mature Graafian follicle during the hours preceding ovulation and culminates in an extreme asymmetric cell division and the segregation of the two pairs of homologous chromosomes. The newly created mature egg rearrests at metaphase of the second meiotic division prior to ovulation and only completes meiosis following a Ca2+ signal initiated by the sperm at gamete fusion. Here, we review the cellular events that govern the passage of the oocyte through meiosis I with a focus on the role of the spindle assembly checkpoint in regulating its timing. In meiosis II, we examine how the egg achieves its arrest and how the fertilization Ca2+ signal allows the initiation of embryo development.

Sign in / Sign up

Export Citation Format

Share Document