Human Diseases from Gain-of-Function Mutations in Disordered Protein Regions.

Although there is much focus on the impact of mutations on structured protein domains, less is known about their impact on unstructured regions. In this issue, Meyer et al. demonstrate that mutations resulting in the emergence of new short linear peptide motifs within intrinsically disordered protein regions can cause human genetic diseases by gain of function.

Dynamics in Fip1 regulate eukaryotic mRNA 3' end processing.

Cleavage and polyadenylation factor (CPF/CPSF) is a multiprotein complex essential for mRNA 3' end processing in eukaryotes. It contains an endonuclease that cleaves pre-mRNAs, and a polymerase that adds a poly(A) tail onto the cleaved 3' end. Several CPF subunits, including Fip1, contain intrinsically disordered regions (IDRs). IDRs within multiprotein complexes can be flexible, or can become ordered upon interaction with binding partners. Here, we show that yeast Fip1 anchors the poly(A) polymerase Pap1 onto CPF via an interaction with zinc finger 4 of another CPF subunit, Yth1. We also reconstitute a fully recombinant 850-kDa CPF. By incorporating selectively labeled Fip1 into recombinant CPF, we could study the dynamics of Fip1 within the megadalton complex using nuclear magnetic resonance (NMR) spectroscopy. This reveals that a Fip1 IDR that connects the Yth1- and Pap1-binding sites remains highly dynamic within CPF. Together, our data suggest that Fip1 dynamics within the 3' end processing machinery are required to coordinate cleavage and polyadenylation.

Classical swine fever virus non-structural protein 5B hijacks host METTL14-mediated m6A modification to counteract host antiviral immune response.

Classical Swine Fever (CSF), caused by the Classical Swine Fever Virus (CSFV), inflicts significant economic losses on the global pig industry. A key factor in the challenge of eradicating this virus is its ability to evade the host's innate immune response, leading to persistent infections. In our study, we elucidate the molecular mechanism through which CSFV exploits m6A modifications to circumvent host immune surveillance, thus facilitating its proliferation. We initially discovered that m6A modifications were elevated both in vivo and in vitro upon CSFV infection, particularly noting an increase in the expression of the methyltransferase METTL14. CSFV non-structural protein 5B was found to hijack HRD1, the E3 ubiquitin ligase for METTL14, preventing METTL14 degradation. MeRIP-seq analysis further revealed that METTL14 specifically targeted and methylated TLRs, notably TLR4. METTL14-mediated regulation of TLR4 degradation, facilitated by YTHDF2, led to the accelerated mRNA decay of TLR4. Consequently, TLR4-mediated NF-κB signaling, a crucial component of the innate immune response, is suppressed by CSFV. Collectively, these data effectively highlight the viral evasion tactics, shedding light on potential antiviral strategies targeting METTL14 to curb CSFV infection.

Nobiletin enhances mitochondrial function by regulating SIRT1/PGC-1α signaling in porcine oocytes during in vitro maturation.

Nobiletin is a natural flavonoid found in citrus fruits with beneficial effects, including anti-inflammatory, anti-cancer and anti-oxidation effects. The aim of this study was to investigate whether nobiletin improves mitochondrial function in porcine oocytes and examine the underlying mechanism. Oocytes enclosed by cumulus cells were cultured in TCM-199 for 44 h with 0.1% dimethyl sulfoxide (control), or supplemented with 5, 10, 25, and 50 µM of nobiletin (Nob5, Nob10, Nob25, and Nob50, respectively). Oocyte maturation rate was significantly enhanced in Nob10 (70.26 ± 0.45%) compared to the other groups (control: 60.12 ± 0.47%; Nob5: 59.44 ± 1.63%; Nob25: 63.15 ± 1.38%; Nob50: 46.57 ± 1.19%). The addition of nobiletin reduced the levels of reactive oxygen species and increased glutathione levels. Moreover, Nob10 promoted mitochondrial biogenesis by upregulating the protein levels of sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α). This resulted in an increase in the number of active mitochondria, mitochondrial DNA copy number, mitochondrial membrane potential, and ATP production, thereby enhancing mitochondrial function. The protein level of p53 decreased, followed by the phosphorylation of B-cell lymphoma 2, suggesting a reduction in mitochondria-mediated apoptosis in the Nob10 group. Additionally, the release of cytochrome c from the mitochondria was significantly diminished along with a decrease in the protein expression of caspase 3. Thus, nobiletin has a great potential to promote the in vitro maturation of porcine oocytes by suppressing oxidative stress and promoting mitochondrial function through the upregulation of the SIRT1/PGC-1α signaling pathway.

GRK2 is critical for the cleavage of the porcine embryo by regulating HSP90 and the AKT pathway.

Among the family of GPCR kinases (GRKs) that regulate receptor phosphorylation and signaling termination, G-protein coupled receptor kinase 2 (GRK2) binds to HSP90 in response to hypoxia or other stresses. In the present study, we investigated the effects of GRK2 knockdown and inhibition on porcine embryonic development from the zygote stage. Immunofluorescence and western blotting were used to determine the localization and expression, respectively, of GRK2 and related proteins. First, GRK2 and p-GRK2 were expressed in both the cytoplasm and membrane and co-localized with HSP90 on the membrane. The mRNA level of GRK2 increased until the 8C- morula stage, suggesting that GRK2 may play an essential role during the early development of the porcine embryos. GRK2 knockdown reduced porcine embryo development capacity and led to significantly decreased blastocyst quality. In addition, inhibition of GRK2 also induced poor ability of embryo development at early stage, indicating that GRK2 is critical for embryonic cleavage in pigs. Knockdown and inhibition of GRK2 reduced HSP90 expression and AKT activation and cAMP levels. Additionally, GRK2 deficiency increased LC3 expression, suggesting enhanced autophagy during embryo development. In summary, we showed that GRK2 binds to HSP90 on the membrane to regulate embryonic cleavage and AKT activation during embryonic development in pigs.

Semisynthesis and antitumor activity of endertiin B and related triterpenoids from Ganoderma lucidum.

Ganoderma lucidum, a fungus used in traditional Chinese medicine, is known for its medicinal value attributed to its active components called Ganoderma triterpenoids (GTs). However, the limited isolation rate of these GTs has hindered their potential as promising drug candidates. Therefore, it is imperative to achieve large-scale preparation of GTs. In this study, four GTs were effectively synthesised from lanosterol. The antitumor activity of these GTs was evaluated in vivo. Endertiin B exhibited potent inhibitory activity against breast cancer cells (9.85 ± 0.91 µM and 12.12 ± 0.95 µM). Further investigations demonstrated that endertiin B significantly upregulated p21 and p27 and downregulated cyclinD1 expression, arresting the cell cycle at the G0/G1 phase and inducing apoptosis by decreasing BCL-2 and increasing BAX and BAK levels. Additionally, endertiin B was found to reduce the expression of proteins associated with the PI3K-AKT signaling pathway. To summarize, endertiin B effectively inhibited cell proliferation by blocking the cell cycle and inducing apoptosis through the PI3K-AKT pathway.

Y-box binding protein 1 influences zygotic genome activation by regulating N6-methyladenosine in porcine embryos.

Y-box binding protein 1 (YBX1) is a member of the family of DNA- and RNA-binding proteins that play crucial roles in multiple aspects, including RNA stabilization, translational repression, and transcriptional regulation; however, its roles in embryo development remain less known. In this study, to investigate the function of YBX1 and its mechanism of action in porcine embryo development, YBX1 was knocked down by microinjecting YBX1 siRNA at the one-cell stage. YBX1 is located in the cytoplasm during embryonic development. The mRNA level of YBX1 was increased from the four-cell stage to the blastocyst stage but was significantly decreased in YBX1 knockdown embryos compared with the control. Moreover, the percentage of blastocysts was decreased following YBX1 knockdown compared with the control. Defecting YBX1 expression increased maternal gene mRNA expression and decreased zygotic genome activation (ZGA) gene mRNA expression and histone modification owing to decreased levels of N6-methyladenosine (m6A) writer N6-adenosine-methyltransferase 70 kDa subunit (METTL3) and reader insulin-like growth factor 2 mRNA-binding protein (IGF2BP1). In addition, IGF2BP1 knockdown showed that YBX1 regulated the ZGA process through m6A modification. In conclusion, YBX1 is essential for early embryo development because it regulates the ZGA process.

LncRNA AGAP2 antisense RNA 1 stabilized by insulin-like growth factor 2 mRNA binding protein 3 promotes macrophage M2 polarization in clear cell renal cell carcinoma through regulation of the microRNA-9-5p/THBS2/PI3K-Akt pathway.

BACKGROUND: Increasing evidence highlights the potential role of long non-coding RNAs (lncRNAs) in the biological behaviors of renal cell carcinoma (RCC). Here, we explored the mechanism of AGAP2-AS1 in the occurrence and development of clear cell RCC (ccRCC) involving IGF2BP3/miR-9-5p/THBS2. METHODS: The expressions of AGAP2-AS1, IGF2BP3, miR-9-5p, and THBS2 and their relationship were analyzed by bioinformatics. The targeting relationship between AGAP2-AS1 and miR-9-5p and between miR-9-5p and THBS2 was evaluated with their effect on cell biological behaviors and macrophage polarization assayed. Finally, we tested the effect of AGAP2-AS1 on ccRCC tumor formation in xenograft tumors. RESULTS: IGF2BP3 could stabilize AGAP2-AS1 through m6A modification. AGAP2-AS1 was highly expressed in ccRCC tissues and cells. The lentivirus-mediated intervention of AGAP2-AS1 induced malignant behaviors of ccRCC cells and led to M2 polarization of macrophages. In addition, THBS2 promoted M2 polarization of macrophages by activating the PI3K/AKT signaling pathway. AGAP2-AS1 could directly bind with miR-9-5p and promote the expression of THBS2 downstream of miR-9-5p. These results were further verified by in vivo experiments. CONCLUSION: AGAP2-AS1 stabilized by IGF2BP3 competitively binds to miR-9-5p to up-regulate THBS2, activating the PI3K/AKT signaling pathway and inducing macrophage M2 polarization, thus facilitating the development of RCC.

Quantum Dots Meet Enzymes: Hydrophobicity of Surface Ligands and Size Do Matter.

Colloidal quantum dots (QDs) are a class of representative fluorescent nanomaterials with tunable, bright, and sharp fluorescent emission, with promising biomedical applications. However, their effects on biological systems are not fully elucidated. In this work, we investigated the interactions between QDs with different surface ligands and different particle sizes and α-chymotrypsin (ChT) from the thermodynamic and kinetic perspectives. Enzymatic activity experiments demonstrated that the catalytic activity of ChT was strongly inhibited by QDs coated with dihydrolipoic acid (DHLA-QDs) with noncompetitive inhibitions, whereas the QDs coated with glutathione (GSH-QDs) had weak effects. Furthermore, kinetics studies showed that different particle sizes of DHLA-QDs all had high suppressive effects on the catalytic activity of ChT. It was found that DHLA-QDs with larger particle sizes had stronger inhibition effects because more ChT molecules were bound onto the surface of QDs. This work highlights the importance of hydrophobic ligands and particle sizes of QDs, which should be considered as the primary influencing factors in the assessment of biosafety. Meanwhile, the results herein can also inspire the design of nano inhibitors.

Tetrahydroberberrubine retards heart aging in mice by promoting PHB2-mediated mitophagy.

Heart aging is characterized by left ventricular hypertrophy and diastolic dysfunction, which in turn induces a variety of cardiovascular diseases. There is still no therapeutic drug to ameliorate cardiac abnormities in heart aging. In this study we investigated the protective effects of berberine (BBR) and its derivative tetrahydroberberrubine (THBru) against heart aging process. Heart aging was induced in mice by injection of D-galactose (D-gal, 120 mg · kg-1 · d-1, sc.) for 12 weeks. Meanwhile the mice were orally treated with berberine (50 mg · kg-1 · d-1) or THBru (25, 50 mg · kg-1 · d-1) for 12 weeks. We showed that BBR and THBru treatment significantly mitigated diastolic dysfunction and cardiac remodeling in D-gal-induced aging mice. Furthermore, treatment with BBR (40 µM) and THBru (20, 40 µM) inhibited D-gal-induced senescence in primary neonatal mouse cardiomyocytes in vitro. Overall, THBru exhibited higher efficacy than BBR at the same dose. We found that the levels of mitophagy were significantly decreased during the aging process in vivo and in vitro, THBru and BBR promoted mitophagy with different potencies. We demonstrated that the mitophagy-inducing effects of THBru resulted from increased mRNA stability of prohibitin 2 (PHB2), a pivotal factor during mitophagy, thereby upregulating PHB2 protein expression. Knockdown of PHB2 effectively reversed the antisenescence effects of THBru in D-gal-treated cardiomyocytes. On the contrary, overexpression of PHB2 promoted mitophagy and retarded cardiomyocyte senescence, as THBru did. In conclusion, this study identifies THBru as a potent antiaging medicine that induces PHB2-mediated mitophagy and suggests its clinical application prospects.

High Temperature-Induced m6A Epigenetic Changes Affect Early Porcine Embryonic Developmental Competence in Pigs.

N6-methyladenosine (m6A), the most prevalent modification in eukaryotic messenger RNA (mRNA), plays a key role in various developmental processes in mammals. Three proteins that affect RNA m6A modification have been identified: methyltransferases, demethylases, and m6A-binding proteins, known as "writer," "eraser," and "reader" proteins, respectively. However, changes in the m6A modification when early porcine embryos are exposed to stress remain unclear. In this study, we exposed porcine oocytes to a high temperature (HT, 41°C) for 10 h, after which the mature oocytes were parthenogenetically activated and cultured for 7 days to the blastocyst stage. HT significantly decreased the rates of the first polar body extrusion and blastocyst formation. Further detection of m6A modification found that HT can lead to increased expression levels of "reader," YTHDF2, and "writer," METTL3, and decreased expression levels of "eraser," FTO, resulting in an increased level of m6A modification in the embryos. Additionally, heat shock protein 70 (HSP70) is upregulated under HT conditions. Our study demonstrated that HT exposure alters m6A modification levels, which further affects early porcine embryonic development.

ZSCAN4 Regulates Zygotic Genome Activation and Telomere Elongation in Porcine Parthenogenetic Embryos.

Zinc finger and SCAN domain-containing 4 (ZSCAN4), a DNA-binding protein, maintains telomere length and plays a key role in critical aspects of mouse embryonic stem cells, including maintaining genomic stability and defying cellular senescence. However, the effect of ZSCAN4 in porcine parthenogenetic embryos remains unclear. To investigate the function of ZSCAN4 and the underlying mechanism in porcine embryo development, ZSCAN4 was knocked down via dsRNA injection in the one-cell stage. ZSCAN4 was highly expressed in the four- and five- to eight-cell stages in porcine embryos. The percentage of four-cell stage embryos, five- to eight-cell stage embryos, and blastocysts was lower in the ZSCAN4 knockdown group than in the control group. Notably, depletion of ZSCAN4 induced the protein expression of DNMT1 and 5-Methylcytosine (5mC, a methylated form of the DNA base cytosine) in the four-cell stage. The H3K27ac level and ZGA genes expression decreased following ZSCAN4 knockdown. Furthermore, ZSCAN4 knockdown led to DNA damage and shortened telomere compared with the control. Additionally, DNMT1-dsRNA was injected to reduce DNA hypermethylation in ZSCAN4 knockdown embryos. DNMT1 knockdown rescued telomere shortening and developmental defects caused by ZSCAN4 knockdown. In conclusion, ZSCAN4 is involved in the regulation of transcriptional activity and is essential for maintaining telomere length by regulating DNMT1 expression in porcine ZGA.

Dignity in nursing: A bibliometric and visual analysis of scientific publications.

BACKGROUND: Dignity-conserved nursing has been widely studied by scholars all over the world; however, there is no clear direction in which this field is trending. AIM: To conduct a bibliometric analysis that systematically characterises publications on dignity research in the nursing field from 2011 to 2020. DESIGN: Bibliometric and visual analysis of retrieved articles. METHODS: The Web of Science Core Collection database was used to retrieve all articles which addressed dignity in nursing from 2011 to 2020. The WoSCC's own analysis tool, CiteSpace and VOSviewer, were used to obtain visual analysis results. Reporting follows the STROBE checklist. RESULTS: A total of 1429 papers on dignity care are included in this study. We found that the number of papers on this topic increased steadily, and the United States topped the list with 366 articles in total. The institute with the most publications was King's College London, and the most widely published journal was Nursing Ethics. We were able to identify four major research topics, namely dignity in: (a) palliative care, (b) dementia and the elderly, (c) health care and (d) nursing ethics. Terminally ill patient, home, value, rehabilitation and psychological distress were the five keywords with the highest burst strength. CONCLUSIONS: The interest in dignity care research has been steadily increasing from 2011 and is reflected in the number of published papers. The United States and Western Europe are leading in this field, both having a high number of cutting-edge researchers and high-level scientific research institutions. In the domain of dignity care, several stable and high-yield core author groups have been formed. While the existing research mainly focuses on four hot spots, psychological distress, advanced cancer, maternity care and content analysis may be the research frontiers.

Effect of thermal process on the key aroma components of green tea with chestnut-like aroma.

BACKGROUND: Chestnut-like aroma is one of the unique qualities of Chinese green tea and has become an important factor influencing consumer decisions. However, the chemical formation mechanism of chestnut-like aroma during green tea processing remains unclear. In this study, the dynamic changes of key components contributing to chestnut-like aroma and their precursors were analyzed in fresh leaves, fixation leaves, first baking tea leaves, and green tea. RESULTS: The thermal process had an important effect on volatile components in tea leaves, causing a significant decrease of alcohols and esters and a significant increase of ketones, acids, phenols, and sulfur compounds. Furthermore, 31 volatiles were identified as the key odorants responsible for chestnut-like aroma of green tea, including dimethyl sulfide, methyl isobutenyl ketone, 2-methylbutanal, 2,4-dimethylstyrene, d-limonene, methyl 2-methylvalerate, linalool, decanal, longifolene, phenylethyl alcohol, l-α-terpineol, jasmone, and so on. And the majority of these odorants were only formed in the drying stage. Additionally, isoleucine, theanine, methionine, and glucose were found to be involved in the formation of chestnut-like aroma of green tea. CONCLUSION: The drying process played a vital important role in the formation of chestnut-like aroma of green tea. © 2022 Society of Chemical Industry.

Rab23/Kif17 regulate meiotic progression in oocytes by modulating tubulin acetylation and actin dynamics.

Cytoskeletal dynamics are involved in multiple cellular processes during oocyte meiosis, including spindle organization, actin-based spindle migration and polar body extrusion. Here, we report that the vesicle trafficking protein Rab23, a GTPase, drives the motor protein Kif17, and that this is important for spindle organization and actin dynamics during mouse oocyte meiosis. GTP-bound Rab23 accumulated at the spindle and promoted migration of Kif17 to the spindle poles. Depletion of Rab23 or Kif17 caused polar body extrusion failure. Further analysis showed that depletion of Rab23/Kif17 perturbed spindle formation and chromosome alignment, possibly by affecting tubulin acetylation. Kif17 regulated tubulin acetylation by associating with αTAT and Sirt2, and depletion of Kif17 altered expression of these proteins. Moreover, depletion of Kif17 decreased the level of cytoplasmic actin, which abrogated spindle migration to the cortex. The tail domain of Kif17 associated with constituents of the RhoA-ROCK-LIMK-cofilin pathway to modulate assembly of actin filaments. Taken together, our results demonstrate that the Rab23-Kif17-cargo complex regulates tubulin acetylation for spindle organization and drives actin-mediated spindle migration during meiosis.

KMT2B promotes the growth of renal cell carcinoma via upregulation of SNHG12 expression and promotion of CEP55 transcription.

BACKGROUND: This study aims to clarify the mechanistic action of long non-coding RNA (lncRNA) SNHG12 in the development of renal cell carcinoma (RCC), which may be associated with promoter methylation modification by KMT2B and the regulation of the E2F1/CEP55 axis. METHODS: TCGA and GEO databases were used to predict the involvement of SNHG12 in RCC. Knockdown of SNHG12/E2F1/CEP55 was performed. Next, SNHG12 expression and other mRNAs were quantified by RT-qPCR. Subsequently, CCK-8 was used to detect cell proliferation. Wound healing assay and Transwell assay were used to detect cell migration and invasion, respectively. The in vitro angiogenesis of human umbilical vein endothelial cells (HUVECs) was explored by matrigel-based capillary-like tube formation assay. ChIP assay was used to detect H3K4me3 in SNHG12 promoter region. The binding of E2F1 to CEP55 promoter region was analyzed with ChIP and dual luciferase reporter assays. RIP assay was used to detect the binding of SNHG12 to E2F1. Finally, the effect of SNHG12 on the tumor formation and angiogenesis of RCC was assessed in nude mouse xenograft model. RESULTS: SNHG12 was highly expressed in RCC tissues and cells, and it was related to the poor prognosis of RCC patients. SNHG12 knockdown significantly inhibited RCC cell proliferation, migration, and invasion and HUVEC angiogenesis. KMT2B up-regulated SNHG12 expression through modifying H3K4me3 in its promoter region. In addition, SNHG12 promoted CEP55 expression by recruiting the transcription factor E2F1. Knockdown of SNHG12 blocked E2F1 recruitment and down-regulated the expression of CEP55, thereby inhibiting tumor formation and angiogenesis in nude mice. CONCLUSION: The evidence provided by our study highlighted the involvement of KMT2B in up-regulation of lncRNA as well as the transcription of CEP55, resulting in the promotion of angiogenesis and growth of RCC.

Kanglexin delays heart aging by promoting mitophagy.

Heart aging is characterized by structural and diastolic dysfunction of the heart. However, there is still no effective drug to prevent and treat the abnormal changes in cardiac function caused by aging. Here, we present the preventive effects of emodin and its derivative Kanglexin (KLX) against heart aging. We found that the diastolic dysfunction and cardiac remodeling in mice with D-galactose (D-gal)-induced aging were markedly mitigated by KLX and emodin. In addition, the senescence of neonatal mouse cardiomyocytes induced by D-gal was also reversed by KLX and emodin treatment. However, KLX exhibited better anti-heart aging effects than emodin at the same dose. Dysregulated mitophagy was observed in aging hearts and in senescent neonatal mouse cardiomyocytes, and KLX produced a greater increase in mitophagy than emodin. The mitophagy-promoting effects of KLX and emodin were ascribed to their abilities to enhance the protein stability of Parkin, a key modulator in mitophagy, with different potencies. Molecular docking and SPR analysis demonstrated that KLX has a higher affinity for the ubiquitin-like (UBL) domain of Parkin than emodin. The UBL domain might contribute to the stabilizing effects of KLX on Parkin. In conclusion, this study identifies KLX and emodin as effective anti-heart aging drugs that activate Parkin-mediated mitophagy and outlines their putative therapeutic importance.

Mps1 controls spindle assembly, SAC, and DNA repair in the first cleavage of mouse early embryos.

Monopolar spindle-1 (Mps1) is a critical interphase regulator that also involves into the spindle assembly checkpoint for the cell cycle control in both mitosis and meiosis. However, the functions of Mps1 during mouse early embryo development is still unclear. In this study, we reported the important roles of Mps1 in the first cleavage of mouse embryos. Our data indicated that the loss of Mps1 activity caused precocious cleavage of zygotes to 2-cell embryos; however, prolonged culture disturbed the early embryo development to the blastocyst. We found that the spindle organization was disrupted after Mps1 inhibition, and the chromosomes were misaligned in the first cleavage. Moreover, the kinetochore-microtubule attachment was lost and Aurora B failed to accumulate to the kinetochores, indicating that the spindle assembly checkpoint (SAC) was activated. Furthermore, the inhibition of Mps1 activity resulted in an increase of DNA damage, which further induced oxidative stress, showing with positive γ-H2A.X signal and increased reactive oxygen species level. Ultimately, irreparable DNA damage and oxidative stress-activated apoptosis and autophagy, which was confirmed by the positive Annexin-V signal and increased autophagosomes. Taken together, our data indicated that Mps1 played important roles in the control of SAC and DNA repair during mouse early embryo development.

Light and Abscisic Acid Coordinately Regulate Greening of Seedlings.

The greening of etiolated seedlings is crucial for the growth and survival of plants. After reaching the soil surface and sunlight, etiolated seedlings integrate numerous environmental signals and internal cues to control the initiation and rate of greening thus to improve their survival and adaption. However, the underlying regulatory mechanisms by which light and phytohormones, such as abscisic acid (ABA), coordinately regulate greening of the etiolated seedlings is still unknown. In this study, we showed that Arabidopsis (Arabidopsis thaliana) DE-ETIOLATED1 (DET1), a key negative regulator of photomorphogenesis, positively regulated light-induced greening by repressing ABA responses. Upon irradiating etiolated seedlings with light, DET1 physically interacts with FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and subsequently associates to the promoter region of the FHY3 direct downstream target ABA INSENSITIVE5 (ABI5). Further, DET1 recruits HISTONE DEACETYLASE6 to the locus of the ABI5 promoter and reduces the enrichments of H3K27ac and H3K4me3 modification, thus subsequently repressing ABI5 expression and promoting the greening of etiolated seedlings. This study reveals the physiological and molecular function of DET1 and FHY3 in the greening of seedlings and provides insights into the regulatory mechanism by which plants integrate light and ABA signals to fine-tune early seedling establishment.

RAB7 GTPase regulates actin dynamics for DRP1-mediated mitochondria function and spindle migration in mouse oocyte meiosis.

RAB7 is a small GTPase that belongs to the Rab family, and as a vesicle trafficking factor it is shown to regulate the transport to late endocytic compartments, autophagosome maturation and organelle function. In present study, we showed the critical roles of RAB7 GTPase on actin dynamics and mitochondria function in oocyte meiosis. RAB7 mainly accumulated at cortex and spindle periphery during oocyte maturation. RAB7 depletion caused the failure of polar body extrusion and asymmetric division, and Rab7 exogenous mRNA supplement could rescue the defects caused by RAB7 RNAi. Based on mass spectrometry analysis, we found that RAB7 associated with several actin nucleation factors and mitochondria-related proteins in oocytes. The depletion of RAB7 caused the decrease of actin dynamics, which further affected meiotic spindle migration to the oocyte cortex. In addition, we found that RAB7 could maintain mitochondrial membrane potential and the mitochondrial distribution in mouse oocytes, and this might be due to its effects on the phosphorylation of DRP1 at Ser616 domain. Taken together, our data indicated that RAB7 transported actin nucleation factor for actin polarization, which further affected the phosphorylation of DRP1 for mitochondria dynamics and the meiotic spindle migration in mouse oocytes.