A novel strategy to map a locus associated with flowering time in canola (Brassica napus L.).

Flowering time is an important agronomic trait for canola breeders, as it provides growers with options for minimizing exposure to heat stress during flowering and to more effectively utilize soil moisture. Plants have evolved various systems to control seasonal rhythms in reproductive phenology including an internal circadian clock that responds to environmental signals. In this study, we used canola cultivar 'Westar' as a recurrent parent and canola cultivar 'Surpass 400' as the donor parent to generate a chromosome segment substitution line (CSSL) and to map a flowering time locus on chromosome A10 using molecular marker-assisted selection. This CSSL contains an introgressed 4.6 mega-bases (Mb) segment (between 13 and 17.6 Mb) of Surpass 400, which substantially delayed flowering compared with Westar. To map flowering time gene(s) within this locus, eight introgression lines (ILs) were developed carrying a series of different lengths of introgressed chromosome A10 segments using five co-dominant polymorphic markers located at 13.5, 14.0, 14.5, 15.0, 15.5, and 16.0 Mb. Eight ILs were crossed with Westar reciprocally and flowering time of resultant 16 F1 hybrids and parents were evaluated in a greenhouse (2021 and 2022). Four ILs (IL005, IL017, IL035, and IL013) showed delayed flowering compared to Westar (P < 0.0001), and their reciprocal crosses displayed a phenotype intermediate in flowering time of both homozygote parents. These results indicated that flowering time is partial or incomplete dominance, and the flowering time locus mapped within a 1 Mb region between two co-dominant polymorphic markers at 14.5-15.5 Mb on chromosome A10. The flowering time locus was delineated to be between 14.60 and 15.5 Mb based on genotypic data at the crossover site, and candidate genes within this region are associated with flowering time in canola and/or Arabidopsis. The co-dominant markers identified on chromosome A10 should be useful for marker assisted selection in breeding programs but will need to be validated to other breeding populations or germplasm accessions of canola.

Potential of observing the diameter of the optic nerve sheath using computed tomography in diagnosing high intracranial pressure in patients with spontaneous CSF rhinorrhea.

KEY POINTS: Spontaneous cerebrospinal fluid rhinorrhea (sCSFR) is often accompanied by an increase in intracranial pressure (ICP). The widening of optic nerve sheath diameter (ONSD) is an indicator of increased ICP. Using CT to measure ONSD is a simple and noninvasive auxiliary method for determining high ICP in sCSFR patients.

Phosphoproteomic analysis reveals the mechanisms of human umbilical cord mesenchymal stem cell-derived exosomes attenuate renal aging.

Aging is a critical biological process, with particularly notable impacts on the kidneys. Exosomes derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) are capable of transferring various bioactive molecules, which exhibit beneficial therapeutic effects on kidney diseases. This study demonstrates that exosomes derived from hUC-MSCs ameliorate cellular senescence in the kidneys of naturally aging mice. These exosomes reduce the protein expression of senescence markers and senescence-associated secretory phenotypes (SASP) leading to fewer DNA damage foci and increased expression of the proliferation indicator Ki67. During the aging process, many proteins undergo phosphorylation modifications. We utilized data-independent acquisition (DIA) phosphoproteomics to study kidneys of naturally aging mice and those treated with hUC-MSC-derived exosomes. We observed elevated phosphorylation levels of the differentially phosphorylated proteins, Lamin A/C, at Ser390 and Ser392 sites, which were subsequently verified by western blotting. Overall, this study provides a new molecular characterization of hUC-MSC-derived exosomes in mitigating cellular senescence in the kidneys. SIGNIFICANCE: DIA phosphoproteomics was employed to investigate phosphorylated proteins in the kidney tissues of naturally aging mice with hUCMSC-exos treated. The results demonstrated that the DIA technique detected a higher abundance of phosphorylated proteins. We identified 24 significantly differentially phosphorylated proteins, and found that the phosphorylation of specific Lamin A/C sites is crucial for preventing cellular senescence. This study will help to better reveal the related phosphorylated proteins involved in hUCMSC-exos intervention in the kidneys of naturally aging mice, providing a foundation for future research on specific phosphorylation sites of proteins as potential therapeutic targets for renal aging-related diseases.

Molecule-Level Multiscale Design of Nonflammable Gel Polymer Electrolyte to Build Stable SEI/CEI for Lithium Metal Battery.

The risk of flammability is an unavoidable issue for gel polymer electrolytes (GPEs). Usually, flame-retardant solvents are necessary to be used, but most of them would react with anode/cathode easily and cause serious interfacial instability, which is a big challenge for design and application of nonflammable GPEs. Here, a nonflammable GPE (SGPE) is developed by in situ polymerizing trifluoroethyl methacrylate (TFMA) monomers with flame-retardant triethyl phosphate (TEP) solvents and LiTFSI-LiDFOB dual lithium salts. TEP is strongly anchored to PTFMA matrix via polarity interaction between -P = O and -CH2CF3. It reduces free TEP molecules, which obviously mitigates interfacial reactions, and enhances flame-retardant performance of TEP surprisingly. Anchored TEP molecules are also inhibited in solvation of Li+, leading to anion-dominated solvation sheath, which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers. Such coordination structure changes Li+ transport from sluggish vehicular to fast structural transport, raising ionic conductivity to 1.03 mS cm-1 and transfer number to 0.41 at 30 °C. The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm-2, and 4.2 V LiCoO2|SGPE|Li battery delivers high average specific capacity > 120 mAh g-1 over 200 cycles. This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.

Genetic drift, historic migration, and limited gene flow contributing to the subpopulation divergence in wild sea beet (Beta vulgaris ssp. maritima (L.) Arcang).

Cultivated beet (Beta vulgaris L. ssp. vulgaris) originated from sea beet (B. vulgaris ssp. maritima (L.) Arcang), a wild beet species widely distributed along the coasts of the Mediterranean Sea and Atlantic Ocean, as well as northern Africa. Understanding the evolution of sea beet will facilitate its efficient use in sugarbeet improvement. We used SNPs (single nucleotide polymorphisms) covering the whole genome to analyze 599 sea beet accessions collected from the north Atlantic Ocean and Mediterranean Sea coasts. All B. maritima accessions can be grouped into eight clusters with each corresponding to a specific geographic region. Clusters 2, 3 and 4 with accessions mainly collected from Mediterranean coasts are genetically close to each other as well as to Cluster 6 that contained mainly cultivated beet. Other clusters were relatively distinct from cultivated beets with Clusters 1 and 5 containing accessions from north Atlantic Ocean coasts, Clusters 7 and Cluster 8 mainly have accessions from northern Egypt and southern Europe, and northwest Morocco, respectively. Distribution of B. maritima subpopulations aligns well with the direction of marine currents that was considered a main dynamic force in spreading B. maritima during evolution. Estimation of genetic diversity indices supported the formation of B. maritima subpopulations due to local genetic drift, historic migration, and limited gene flow. Our results indicated that B. maritima originated from southern Europe and then spread to other regions through marine currents to form subpopulations. This research provides vital information for conserving, collecting, and utilizing wild sea beet to sustain sugarbeet improvement.

S100A8/A9-activated IFNγ+ NK cells trigger ß-cell necroptosis in hepatitis B virus-associated liver cirrhosis.

BACKGROUND AND AIMS: Hepatitis B virus (HBV)-associated liver cirrhosis (LC), a common condition with high incidence and mortality rates, is often associated with diabetes mellitus (DM). However, the molecular mechanisms underlying impaired glucose regulation during HBV-associated LC remain unclear. METHODS: Data from 63 patients with LC and 62 patients with LC-associated DM were analysed. Co-culture of NK cells and islet ß cell lines were used to study the glucose regulation mechanism. A mouse model of LC was used to verify the effect of S100A8/A9 on the glucose regulation. RESULTS: Higher levels of interferon (IFN)-γ derived from natural killer (NK) cells and lower levels of insulin emerged in the peripheral blood of patients with both LC and DM compared with those from patients with LC only. IFN-γ derived from NK cells facilitated ß cell necroptosis and impaired insulin production. Furthermore, S100A8/A9 elevation in patients with both LC and DM was found to upregulate IFN-γ production in NK cells. Consistently, in the mouse model for LC, mice treated with carbon tetrachloride (CCL4) and S100A8/A9 exhibited increased blood glucose, impaired insulin production, increased IFN-γ, and increased ß cells necroptosis compared with those treated with CCL4. Mechanistically, S100A8/A9 activated the p38 MAPK pathway to increase IFN-γ production in NK cells. These effects were diminished after blocking RAGE. CONCLUSION: Together, the data indicate that IFN-γ produced by NK cells induces ß cell necroptosis via the S100A8/A9-RAGE-p38 MAPK axis in patients with LC and DM. Reduced levels of S100A8/A9, NK cells, and IFN-γ could be valuable for the treatment of LC with DM. Accumulation of S100A8/A9 in patients with LC may indicate the emergence of DM.

The features analysis of hemoglobin expression on visual information transmission pathway in early stage of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized primarily by cognitive impairment. The motivation of this paper is to explore the impact of the visual information transmission pathway (V-H pathway) on AD, and the following feature were observed: Hemoglobin expression on the V-H pathway becomes dysregulated as AD occurs so as to the pathway becomes dysfunctional. According to the feature, the following conclusion was proposed: As AD occurs, abnormal tau proteins penetrate bloodstream and arrive at the brain regions of the pathway. Then the tau proteins or other toxic substances attack hemoglobin molecules. Under the attack, hemoglobin expression becomes more dysregulated. The dysfunction of V-H pathway has an impact on early symptoms of AD, such as spatial recognition disorder and face recognition disorder.

Genome-wide association studies on resistance to powdery mildew in cultivated emmer wheat.

Powdery mildew, caused by the fungal pathogen Blumeria graminis (DC.) E. O. Speer f. sp. tritici Em. Marchal (Bgt), is a constant threat to global wheat (Triticum aestivum L.) production. Although ∼100 powdery mildew (Pm) resistance genes and alleles have been identified in wheat and its relatives, more is needed to minimize Bgt's fast evolving virulence. In tetraploid wheat (Triticum turgidum L.), wild emmer wheat [T. turgidum ssp. dicoccoides (Körn. ex Asch. & Graebn.) Thell.] accessions from Israel have contributed many Pm resistance genes. However, the diverse genetic reservoirs of cultivated emmer wheat [T. turgidum ssp. dicoccum (Schrank ex Schübl.) Thell.] have not been fully exploited. In the present study, we evaluated a diverse panel of 174 cultivated emmer accessions for their reaction to Bgt isolate OKS(14)-B-3-1 and found that 66% of accessions, particularly those of Ethiopian (30.5%) and Indian (6.3%) origins, exhibited high resistance. To determine the genetic basis of Bgt resistance in the panel, genome-wide association studies were performed using 46,383 single nucleotide polymorphisms (SNPs) from genotype-by-sequencing and 4331 SNPs from the 9K SNP Infinium array. Twenty-five significant SNP markers were identified to be associated with Bgt resistance, of which 21 SNPs are likely novel loci, whereas four possibly represent emmer derived Pm4a, Pm5a, PmG16, and Pm64. Most novel loci exhibited minor effects, whereas three novel loci on chromosome arms 2AS, 3BS, and 5AL had major effect on the phenotypic variance. This study demonstrates cultivated emmer as a rich source of powdery mildew resistance, and the resistant accessions and novel loci found herein can be utilized in wheat breeding programs to enhance Bgt resistance in wheat.

Association mapping of tan spot and septoria nodorum blotch resistance in cultivated emmer wheat.

KEY MESSAGE: A total of 65 SNPs associated with resistance to tan spot and septoria nodorum blotch were identified in a panel of 180 cultivated emmer accessions through association mapping Tan spot and septoria nodorum blotch (SNB) are foliar diseases caused by the respective fungal pathogens Pyrenophora tritici-repentis and Parastagonospora nodorum that affect global wheat production. To find new sources of resistance, we evaluated a panel of 180 cultivated emmer wheat (Triticum turgidum ssp. dicoccum) accessions for reactions to four P. tritici-repentis isolates Pti2, 86-124, 331-9 and DW5, two P. nodorum isolate, Sn4 and Sn2000, and four necrotrophic effectors (NEs) produced by the pathogens. About 8-36% of the accessions exhibited resistance to the four P. tritici-repentis isolates, with five accessions demonstrating resistance to all isolates. For SNB, 64% accessions showed resistance to Sn4, 43% to Sn2000 and 36% to both isolates, with Spain (11% accessions) as the most common origin of resistance. To understand the genetic basis of resistance, association mapping was performed using SNP (single nucleotide polymorphism) markers generated by genotype-by-sequencing and the 9 K SNP Infinium array. A total of 46 SNPs were significantly associated with tan spot and 19 SNPs with SNB resistance or susceptibility. Six trait loci on chromosome arms 1BL, 3BL, 4AL (2), 6BL and 7AL conferred resistance to two or more isolates. Known NE sensitivity genes for disease development were undetected except Snn5 for Sn2000, suggesting novel genetic factors are controlling host-pathogen interaction in cultivated emmer. The emmer accessions with the highest levels of resistance to the six pathogen isolates (e.g., CItr 14133-1, PI 94634-1 and PI 377672) could serve as donors for tan spot and SNB resistance in wheat breeding programs.

[Comparison of 5-year survival rate and analysis of prognostic factors influencing the prognosis of adenoid cystic carcinoma and squamous cell carcinoma of the maxillary sinus: based on the SEER database].

Objective:To analyze the difference in 5-year survival between maxillary sinus adenoidal cystic carcinoma（maxillary sinus adenoid cystic carcinoma, MSACC） and squamous cell carcinoma（maxillary sinus squamous cell carcinoma, MSSCC） using the National Cancer Institute's Surveillance, Epidemiology, and End. Results:database（SEER） and to explore the factors associated with the prognosis of the two tumors. Methods:The data of 161 patients with MSACC and 929 patients with MSSCC were collected from SEER database, and the 5-year overall survival rate（OS） and tumor specific survival rate（CSS） were compared between the two groups before and after propensity score matching. The forest map of multivariate Cox proportional hazard regression model was established to analyze the prognostic factors affecting the survival rate of patients with MSACC and MSSCC. Results:There were statistical differences in 5-year OS and CSS between MSACC and MSSCC before and after propensity score matching（P<0.001）. Multivariate regression analysis showed that age, side of the disease, lymph node metastasis, operation and radiotherapy were the influencing factors of OS in MSACC, while age and operation were the influencing factors of CSS. Age, race, T grade, lymph node metastasis, systemic metastasis, surgery, radiotherapy and chemotherapy are the influencing factors of OS of MSSCC. Age, T grade, lymph node metastasis, systemic metastasis, surgery, radiotherapy and chemotherapy are the influencing factors of CSS. Conclusion:The 5-year survival rate of MSACC is higher than that of MSSCC. Surgery plays a positive role in the prognosis of the two kinds of tumors. The analysis results can provide some reference for their survival expectations and treatment choices.

Cytoskeletal gene alterations linked to sorafenib resistance in hepatocellular carcinoma.

BACKGROUND: Although sorafenib has been consistently used as a first-line treatment for advanced hepatocellular carcinoma (HCC), most patients will develop resistance, and the mechanism of resistance to sorafenib needs further study. METHODS: Using KAS-seq technology, we obtained the ssDNA profiles within the whole genome range of SMMC-7721 cells treated with sorafenib for differential analysis. We then intersected the differential genes obtained from the analysis of hepatocellular carcinoma patients in GSE109211 who were ineffective and effective with sorafenib treatment, constructed a PPI network, and obtained hub genes. We then analyzed the relationship between the expression of these genes and the prognosis of hepatocellular carcinoma patients. RESULTS: In this study, we identified 7 hub ERGs (ACTB, CFL1, ACTG1, ACTN1, WDR1, TAGLN2, HSPA8) related to drug resistance, and these genes are associated with the cytoskeleton. CONCLUSIONS: The cytoskeleton is associated with sorafenib resistance in hepatocellular carcinoma. Using KAS-seq to analyze the early changes in tumor cells treated with drugs is feasible for studying the drug resistance of tumors, which provides reference significance for future research.

Multi-omics reveals the role of MCM2 and hnRNP K phosphorylation in mouse renal aging through genomic instability.

The process of aging is characterized by structural degeneration and functional decline, as well as diminished adaptability and resistance. The aging kidney exhibits a variety of structural and functional impairments. In aging mice, thinning and graying of fur were observed, along with a significant increase in kidney indices compared to young mice. Biochemical indicators revealed elevated levels of creatinine, urea nitrogen and serum uric acid, suggesting impaired kidney function. Histological analysis unveiled glomerular enlargement and sclerosis, severe hyaline degeneration, capillary occlusion, lymphocyte infiltration, tubular and glomerular fibrosis, and increased collagen deposition. Observations under electron microscopy showed thickened basement membranes, altered foot processes, and increased mesangium and mesangial matrix. Molecular marker analysis indicated upregulation of aging-related ß-galactosidase, p16-INK4A, and the DNA damage marker γH2AX in the kidneys of aged mice. In metabolomics, a total of 62 significantly different metabolites were identified, and 10 pathways were enriched. We propose that citrulline, dopamine, and indoxyl sulfate have the potential to serve as markers of kidney damage related to aging in the future. Phosphoproteomics analysis identified 6656 phosphosites across 1555 proteins, annotated to 62 pathways, and indicated increased phosphorylation at the Ser27 site of Minichromosome maintenance complex component 2 (Mcm2) and decreased at the Ser284 site of heterogeneous nuclear ribonucleoprotein K (hnRNP K), with these modifications being confirmed by western blotting. The phosphorylation changes in these molecules may contribute to aging by affecting genome stability. Eleven common pathways were detected in both omics, including arginine biosynthesis, purine metabolism and biosynthesis of unsaturated fatty acids, etc., which are closely associated with aging and renal insufficiency.

CTRP9 alleviates diet induced obesity through increasing lipolysis mediated by enhancing autophagy-initiation complex formation.

Recently, emerging evidence has suggested that obesity become a prevalent health threat worldwide. Reportedly, CTRP9 can ameliorate HFD induced obesity. However, the molecular mechanism underlying the role of CTRP9 in obesity remains elusive. In this study, we reported its major function in the regulation of lipolysis. First, we found that the expression of CTRP9 was decreased in mature adipocytes and white adipose tissue of obese mice. Then, we showed that overexpression adipose tissue CTRP9 alleviated diet-induced obesity and adipocytes hypertrophy, improved glucose intolerance and raised energy expenditure. Moreover, CTRP9 increased the lipolysis in vitro and vivo. Additionally, we determined that CTRP9 enhanced autophagy flux in adipocytes. Intriguingly, knock down Beclin1 by SiRNA abolished the effect of CTRP9 on lipolysis. Mechanically, CTRP9 enhanced the expression of SNX26. We demonstrated that SNX26 was a component of the ATG14L-Beclin1-VPS34 complex and enhanced the assembly of the autophagy-initiation complex. Collectively, our results suggested that CTRP9 alleviated diet induced obesity through enhancing lipolysis mediated by autophagy-initiation complex formation.

Biosynthetic deficiency of docosahexaenoic acid causes nonalcoholic fatty liver disease and ferroptosis-mediated hepatocyte injury.

Exogenous omega-3 fatty acids, particularly docosahexaenoic acid (DHA), have shown to exert beneficial effects on nonalcoholic fatty liver disease (NAFLD), which is characterized by the excessive accumulation of lipids and chronic injury in the liver. However, the effect of endogenous DHA biosynthesis on the lipid homeostasis of liver is poorly understood. In this study, we used a DHA biosynthesis-deficient zebrafish model, elovl2 mutant, to explore the effect of endogenously biosynthesized DHA on hepatic lipid homeostasis. We found the pathways of lipogenesis and lipid uptake were strongly activated, while the pathways of lipid oxidation and lipid transport were inhibited in the liver of elovl2 mutants, leading to lipid droplet accumulation in the mutant hepatocytes and NAFLD. Furthermore, the elovl2 mutant hepatocytes exhibited disrupted mitochondrial structure and function, activated endoplasmic reticulum stress, and hepatic injury. We further unveiled that the hepatic cell death and injury was mainly mediated by ferroptosis, rather than apoptosis, in elovl2 mutants. Elevating DHA content in elovl2 mutants, either by the introduction of an omega-3 desaturase (fat1) transgene or by feeding with a DHA-rich diet, could strongly alleviate NAFLD features and ferroptosis-mediated hepatic injury. Together, our study elucidates the essential role of endogenous DHA biosynthesis in maintaining hepatic lipid homeostasis and liver health, highlighting that DHA deficiency can lead to NAFLD and ferroptosis-mediated hepatic injury.

New insights into the all-testis differentiation in zebrafish with compromised endogenous androgen and estrogen synthesis.

The regulatory mechanism of gonadal sex differentiation, which is complex and regulated by multiple factors, remains poorly understood in teleosts. Recently, we have shown that compromised androgen and estrogen synthesis with increased progestin leads to all-male differentiation with proper testis development and spermatogenesis in cytochrome P450 17a1 (cyp17a1)-/- zebrafish. In the present study, the phenotypes of female-biased sex ratio were positively correlated with higher Fanconi anemia complementation group L (fancl) expression in the gonads of doublesex and mab-3 related transcription factor 1 (dmrt1)-/- and cyp17a1-/-;dmrt1-/- fish. The additional depletion of fancl in cyp17a1-/-;dmrt1-/- zebrafish reversed the gonadal sex differentiation from all-ovary to all-testis (in cyp17a1-/-;dmrt1-/-;fancl-/- fish). Luciferase assay revealed a synergistic inhibitory effect of Dmrt1 and androgen signaling on fancl transcription. Furthermore, an interaction between Fancl and the apoptotic factor Tumour protein p53 (Tp53) was found in vitro. The interaction between Fancl and Tp53 was observed via the WD repeat domain (WDR) and C-terminal domain (CTD) of Fancl and the DNA binding domain (DBD) of Tp53, leading to the K48-linked polyubiquitination degradation of Tp53 activated by the ubiquitin ligase, Fancl. Our results show that testis fate in cyp17a1-/- fish is determined by Dmrt1, which is thought to stabilize Tp53 by inhibiting fancl transcription during the critical stage of sexual fate determination in zebrafish.

Estrogen Signaling Inhibits the Expression of anti-Müllerian hormone (amh) and gonadal-soma-derived factor (gsdf) during the Critical Time of Sexual Fate Determination in Zebrafish.

The mechanism of fish gonadal sex differentiation is complex and regulated by multiple factors. It has been widely known that proper steroidogenesis in Leydig cells and sex-related genes in Sertoli cells play important roles in gonadal sex differentiation. In teleosts, the precise interaction of these signals during the sexual fate determination remains elusive, especially their effect on the bi-potential gonad during the critical stage of sexual fate determination. Recently, all-testis phenotypes have been observed in the cyp17a1-deficient zebrafish and common carp, as well as in cyp19a1a-deficient zebrafish. By mating cyp17a1-deficient fish with transgenic zebrafish Tg(piwil1:EGFP-nanos3UTR), germ cells in the gonads were labelled with enhanced green fluorescent protein (EGFP). We classified the cyp17a1-deficient zebrafish and their control siblings into primordial germ cell (PGC)-rich and -less groups according to the fluorescence area of the EGFP labelling. Intriguingly, the EGFP-labelled bi-potential gonads in cyp17a1+/+ fish from the PGC-rich group were significantly larger than those of the cyp17a1-/- fish at 23 days post-fertilization (dpf). Based on the transcriptome analysis, we observed that the cyp17a1-deficient fish of the PGC-rich group displayed a significantly upregulated expression of amh and gsdf compared to that of control fish. Likewise, the upregulated expressions of amh and gsdf were observed in cyp19a1a-deficient fish as examined at 23 dpf. This upregulation of amh and gsdf could be repressed by treatment with an exogenous supplement of estradiol. Moreover, tamoxifen, an effective antagonist of both estrogen receptor α and ß (ERα and Erß), upregulates the expression of amh and gsdf in wild-type (WT) fish. Using the cyp17a1- and cyp19a1a-deficient zebrafish, we provide evidence to show that the upregulated expression of amh and gsdf due to the compromised estrogen signaling probably determines their sexual fate towards testis differentiation. Collectively, our data suggest that estrogen signaling inhibits the expression of amh and gsdf during the critical time of sexual fate determination, which may broaden the scope of sex steroid hormones in regulating gonadal sex differentiation in fish.

Endogenous biosynthesis of docosahexaenoic acid (DHA) regulates fish oocyte maturation by promoting pregnenolone production.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), particularly docosahexaenoic acid (22:6n-3, DHA), play crucial roles in the reproductive health of vertebrates, including humans. Nevertheless, the underlying mechanism related to this phenomenon remains largely unknown. In this study, we employed two zebrafish genetic models, i.e., elovl2 -/- mutant as an endogenous DHA-deficient model and fat1 (omega-3 desaturase encoding gene) transgenic zebrafish as an endogenous DHA-rich model, to investigate the effects of DHA on oocyte maturation and quality. Results show that the elovl2 -/- mutants had much lower fecundity and poorer oocyte quality than the wild-type controls, while the fat1 zebrafish had higher fecundity and better oocyte quality than wild-type controls. DHA deficiency in elovl2 -/- embryos led to defects in egg activation, poor microtubule stability, and reduced pregnenolone levels. Further study revealed that DHA promoted pregnenolone synthesis by enhancing transcription of cyp11a1, which encodes the cholesterol side-chain cleavage enzyme, thereby stabilizing microtubule assembly during oogenesis. In turn, the hypothalamic-pituitary-gonadal axis was enhanced by DHA. In conclusion, using two unique genetic models, our findings demonstrate that endogenously synthesized DHA promotes oocyte maturation and quality by promoting pregnenolone production via transcriptional regulation of cyp11a1.

COP9 signalosome-mediated deneddylation of CULLIN1 is necessary for SCFEBF1 assembly in Arabidopsis thaliana.

Functions of the SKP1-CUL1-F box (SCF) ubiquitin E3 ligases are essential in plants. The F box proteins (FBPs) are substrate receptors that recruit substrates and assemble an active SCF complex, but the regulatory mechanism underlying the FBPs binding to CUL1 to activate the SCF cycle is not fully understood. We show that Arabidopsis csn1-10 is defective in SCFEBF1-mediated PIF3 degradation during de-etiolation, due to impaired association of EBF1 with CUL1 in csn1-10. EBF1 preferentially associates with un-neddylated CUL1 that is deficient in csn1-10 and the EBF1-CUL1 binding is rescued by the neddylation inhibitor MLN4924. Furthermore, we identify a subset of FBPs with impaired binding to CUL1 in csn1-10, indicating their assembly to form SCF complexes may depend on COP9 signalosome (CSN)-mediated deneddylation of CUL1. This study reports that a key role of CSN-mediated CULLIN deneddylation is to gate the binding of the FBP-substrate module to CUL1, thus initiating the SCF cycle of substrate ubiquitination.