Geminiviruses cause substantial crop yield losses worldwide. The replication initiator protein (Rep) encoded by geminiviruses is indispensable for geminiviral replication. The Rep protein encoded by beet severe curly top virus (BSCTV, genus Curtovirus, family Geminiviridae) induces VARIANT IN METHYLATION 5 (VIM5) expression in Arabidopsis leaves upon BSCTV infection. VIM5 functions as a ubiquitination-related E3 ligase to promote the proteasomal degradation of methyltransferases, resulting in reduction of methylation levels in the BSCTV C2-3 promoter. However, the specific domains of Rep responsible for VIM5 induction remain poorly characterized. Although Rep proteins from several geminiviruses act as viral suppressors of RNA silencing (VSRs), whether BSCTV Rep also possesses VSR activity remains to be illustrated. In this study, we employed a transient expression system in the 16c-GFP transgenic and the wild-type Nicotiana benthamiana plants to analyze the VSR and the VIM5-inducing activities of different truncated Rep proteins haboring distinct domains. We found that the N-terminal domain (amino acids 1-180) of Rep suppressed GFP silencing in 16c-GFP transgenic N. benthamiana leaves. The minimal N-terminal fragment (amino acids 1-104) induced VIM5 expression upon co-infiltration, while C-terminal truncations lacked VIM5-inducing activity. Our results indicate that the N-terminal domain of Rep encoded by BSCTV mediates the suppression of RNA silencing and induces VIM5 expression. Thus, our findings contribute to a better understanding of interactions between geminiviral Rep and plant hosts.
Geminiviridae/genetics* ; Nicotiana/metabolism* ; Arabidopsis/metabolism* ; RNA Interference ; Viral Proteins/metabolism* ; Arabidopsis Proteins/metabolism* ; Plants, Genetically Modified/metabolism* ; Protein Domains ; Plant Diseases/virology* ; Methyltransferases/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; DNA Helicases/genetics*

OBJECTIVES: To investigate the effect of nuclear protein (Nupr) 1 on the pathological progression of osteoarthritis and its relationship with ferroptosis of chondrocytes. METHODS: Chondrocytes from mouse knees were divided into small interfering RNA (siRNA) control group, small interfering RNA targeting Nupr1 (siNupr1) group, siRNA control+IL-1β group (siRNA control interference for 24 h followed by 10 ng/mL IL-1β) and siNupr1+IL-1β group (siNupr1 interference for 24 h followed by 10 ng/mL IL-1β). The protein and mRNA expressions of Nupr1 were detected by Western blotting and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell proliferation viabilities were measured using the cell counting kit-8 method. The levels of ferrous ions were detected by FerroOrange staining. Lipid peroxidation levels were detected by C11-BODIPY-591 fluorescence imaging. The contents of malondialdehyde (MDA) and glutathione (GSH) were detected by enzyme-linked immunosorbent assay. The protein expressions of acyl-CoA synthetase long-chain family (ACSL) 4, P53, glutathione peroxidase (GPX) 4 and solute carrier family 7 member 11 gene (SLC7A11) were detected by Western blotting. The osteoarthritis model was constructed by destabilization of the medial meniscus (DMM) surgery in 7-week-old male C57BL/6J mice. The mice were randomly divided into four groups with 10 animals in each group: sham surgery (Sham)+adeno-associated virus serotype 5 (AAV5)-short hairpin RNA (shRNA) control group, Sham+AAV5-shRNA control targeting Nupr1 (shNupr1) group, DMM+AAV5-shRNA control group, and DMM+AAV5-shNupr1 group. Hematoxylin and eosin staining and Safranin O-Fast Green staining were used to observe the morphological changes in cartilage tissue. The Osteoarthritis Research Society International (OARSI) osteoarthritis cartilage histopathology assessment system was used to evaluate the degree of cartilage degeneration in mice. The mRNA expressions of matrix metallopeptidase (MMP) 13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5, cyclooxy-genase (COX) 2, and GPX4 were detected by qRT-PCR. RESULTS: In vitro experiments showed that knocking down Nupr1 alleviated the decrease of chondrocyte proliferation activity induced by IL-1β, reduced iron accumulation in mouse chondrocytes, lowered lipid peroxidation, downregulated ACSL4 and P53 protein expression and upregulated GPX4 and SLC7A11 protein expression (all P<0.01), thereby inhibiting ferroptosis in mouse chondrocytes. Meanwhile, in vivo animal experiments demonstrated that knocking down Nupr1 delayed the degeneration of articular cartilage in osteoarthritis mice, improved the OARSI score, slowed down the degradation of the extracellular matrix in osteoarthritis cartilage, and reduced the expression of the key ferroptosis regulator GPX4 (all P<0.01). CONCLUSIONS Knockdown of Nupr1 can delay the pathological progression of osteoarthritis through inhibiting ferroptosis in mouse chondrocytes.
Animals ; Ferroptosis ; Mice ; Chondrocytes/metabolism* ; Osteoarthritis/pathology* ; RNA, Small Interfering/genetics* ; Basic Helix-Loop-Helix Transcription Factors/genetics* ; Interleukin-1beta/metabolism* ; Phospholipid Hydroperoxide Glutathione Peroxidase/genetics* ; Coenzyme A Ligases/genetics* ; Tumor Suppressor Protein p53/metabolism* ; Mice, Inbred C57BL ; DNA-Binding Proteins ; Neoplasm Proteins ; Amino Acid Transport System y+ ; Nuclear Receptor Subfamily 1, Group D, Member 1

Brain development requires a delicate balance between self-renewal and differentiation in neural stem cells (NSC), which rely on the precise regulation of gene expression. Ten-eleven translocation 2 (TET2) modulates gene expression by the hydroxymethylation of 5-methylcytosine in DNA as an important epigenetic factor and participates in the neuronal differentiation. Yet, the regulation of TET2 in the process of neuronal differentiation remains unknown. Here, the protein level of TET2 was reduced by the ubiquitin-proteasome pathway during NSC differentiation, in contrast to mRNA level. We identified that TET2 physically interacts with the core subunits of the glucose-induced degradation-deficient (GID) ubiquitin ligase complex, an evolutionarily conserved ubiquitin ligase complex and is ubiquitinated by itself. The protein levels of GID complex subunits increased reciprocally with TET2 level upon NSC differentiation. The silencing of the core subunits of the GID complex, including WDR26 and ARMC8, attenuated the ubiquitination and degradation of TET2, increased the global 5-hydroxymethylcytosine levels, and promoted the differentiation of the NSC. TET2 level increased in the brain of the Wdr26^+/- mice. Our results illustrated that the GID complex negatively regulates TET2 protein stability, further modulates NSC differentiation, and represents a novel regulatory mechanism involved in brain development.
Animals ; Mice ; DNA-Binding Proteins/genetics* ; Cell Differentiation ; Neural Stem Cells ; Translocation, Genetic ; Ubiquitins/genetics* ; Ligases/genetics*

OBJECTIVE: To explore the role of a new blood-based, multiomics and multidimensional method for evaluating the efficacy of patients with lymphoma. METHODS: 10 ml peripheral blood was extracted from each patient, and the genomic copy number aberrations (CNA) and fragment size (FS) were evaluated by low-depth whole genome sequencing of cfDNA, and the level of a group of plasma tumor marker (PTM) were detected at the same time. The cancer efficacy score (CES) was obtained by standardized transformation of the value of above three numerical indexes, and the changes of CES before and after treatment were compared to evaluate the patient's response to the treatment regimen. RESULTS: A total of 35 patients' baseline data were collected, of which 23 cases (65.7%) had elevated CES values. 18 patients underwent the first time test. The results showed that the CES value of 9 patients with positive baseline CES decreased significantly at the first test, and the efficacy evaluation was PR, which was highly consistent with the imaging evaluation results of the same period. At the same time, the CNA variation spectrum of all patients were evaluated and it was found that 23 patients had partial amplification or deletion of chromosome fragments. The most common amplification site was 8q24.21, which contains important oncogenes such as MYC. The most common deletion sites were 1p36.32, 4q21.23, 6q21, 6q27, 14q32.33, and tumor suppressor-related genes such as PRDM1, ATG5, AIM1, FOXO3 and HACE1 were expressed in the above regions, so these deletions may be related to the occurrence and development of lymphoma. CONCLUSION With the advantages of more convenience, sensitivity and non-invasive, this multiomics and multidimensional efficacy detection method can evaluate the tumor load of patients with lymphoma at the molecular level, and make more accurate efficacy evaluation, which is expected to serve the clinic better.
Humans ; Multiomics ; Lymphoma/genetics* ; Cell-Free Nucleic Acids ; Genomics/methods* ; DNA Copy Number Variations ; Ubiquitin-Protein Ligases

OBJECTIVE: To analyze the distribution characteristics of hereditary peripheral neuropathy (HPN) pathogenic genes in Chinese Han population, and to explore the potential pathogenesis and treatment prospects of HPN and related diseases. METHODS: Six hundred and fifty-six index patients with HPN were enrolled in Peking University Third Hospital and China-Japan Friendship Hospital from January 2007 to May 2022. The PMP22 duplication and deletion mutations were screened and validated by multiplex ligation probe amplification technique. The next-generation sequencing gene panel or whole exome sequencing was used, and the suspected genes were validated by Sanger sequencing. RESULTS: Charcot-Marie-Tooth (CMT) accounted for 74.3% (495/666) of the patients with HPN, of whom 69.1% (342/495) were genetically confirmed. The most common genes of CMT were PMP22 duplication, MFN2 and GJB1 mutations, which accounted for 71.3% (244/342) of the patients with genetically confirmed CMT. Hereditary motor neuropathy (HMN) accounted for 16.1% (107/666) of HPN, and 43% (46/107) of HPN was genetically confirmed. The most common genes of HMN were HSPB1, aminoacyl tRNA synthetases and SORD mutations, which accounted for 56.5% (26/46) of the patients with genetically confirmed HMN. Most genes associated with HMN could cause different phenotypes. HMN and CMT shared many genes (e.g. HSPB1, GARS, IGHMBP2). Some genes associated with dHMN-plus shared genes associated with amyotrophic lateral sclerosis (KIF5A, FIG4, DCTN1, SETX, VRK1), hereditary spastic paraplegia (KIF5A, ZFYVE26, BSCL2) and spinal muscular atrophy (MORC2, IGHMBP, DNAJB2), suggesting that HMN was a continuum rather than a distinct entity. Hereditary sensor and autosomal neuropathy (HSAN) accounted for a small proportion of 2.6% (17/666) in HPN. The most common pathogenic gene was SPTLC1 mutation. TTR was the main gene causing hereditary amyloid peripheral neuropathy. The most common types of gene mutations were p.A117S and p.V50M. The symptoms were characterized by late-onset and prominent autonomic nerve involvement. CONCLUSION CMT and HMN are the most common diseases of HPN. There is a large overlap between HMN and motor-CMT2 pathogenic genes, and some HMN pathogenic genes overlap with amyotrophic lateral sclerosis, hereditary spastic hemiplegia and spinal muscular atrophy, suggesting that there may be a potential common pathogenic pathway between different diseases.
Amyotrophic Lateral Sclerosis ; Charcot-Marie-Tooth Disease/genetics* ; DNA Helicases/genetics* ; DNA-Binding Proteins/genetics* ; Flavoproteins ; HSP40 Heat-Shock Proteins ; Humans ; Intracellular Signaling Peptides and Proteins/genetics* ; Kinesins ; Ligases/genetics* ; Molecular Chaperones ; Multifunctional Enzymes ; Muscular Atrophy, Spinal/genetics* ; Mutation ; Phosphoric Monoester Hydrolases ; Protein Serine-Threonine Kinases ; RNA Helicases/genetics* ; RNA, Transfer ; Transcription Factors/genetics*

Cullin-RING E3 ubiquitin ligase (CRL)-4 is a member of the large CRL family in eukaryotes. It plays important roles in a wide range of cellular processes, organismal development, and physiological and pathological conditions. DDB1- and CUL4-associated factor 8 (DCAF8) is a WD40 repeat-containing protein, which serves as a substrate receptor for CRL4. The physiological role of DCAF8 is unknown. In this study, we constructed Dcaf8 knockout mice. Homozygous mice were viable with no noticeable abnormalities. However, the fertility of Dcaf8-deficient male mice was markedly impaired, consistent with the high expression of DCAF8 in adult mouse testis. Sperm movement characteristics, including progressive motility, path velocity, progressive velocity, and track speed, were significantly lower in Dcaf8 knockout mice than in wild-type (WT) mice. However, the total motility was similar between WT and Dcaf8 knockout sperm. More than 40% of spermatids in Dcaf8 knockout mice showed pronounced morphological abnormalities with typical bent head malformation. The acrosome and nucleus of Dcaf8 knockout sperm looked similar to those of WT sperm. In vitro tests showed that the fertilization rate of Dcaf8 knockout mice was significantly reduced. The results demonstrated that DCAF8 plays a critical role in spermatogenesis, and DCAF8 is a key component of CRL4 function in the reproductive system.
Animals ; Cullin Proteins/genetics* ; DNA-Binding Proteins/genetics* ; Factor VIII ; Male ; Mice ; Mice, Knockout ; Spermatogenesis/genetics* ; Ubiquitin-Protein Ligases

OBJECTIVE: To explore the genetic basis for a patient featuring multiple carboxylase deficiency (MCD). METHODS: PCR and Sanger sequencing were used to detect variant in the coding region of BT and HLCS genes in the patient. Suspected variants were verified in her parents and 80 unrelated healthy controls by a PCR-restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: The patient was found to carry compound heterozygous variants of the HLCS gene, namely c.286delG (p.Val96Leufs*162) and c.1648G>A (p.Val550Met). The c.286delG (p.Val96Leufs*162) was verified to be novel variant based on the result of PCR-RFLP analysis. No variant was found in the coding regions of BT gene in the patient. CONCLUSION The compound c.286delG (p.Val96Leufs*162) and c.1648G>A (p.Val550Met) variants probably underlie the MCD disorder in this patient. Above results have enriched the variant spectrum of MCA.
Carbon-Nitrogen Ligases ; genetics ; Exons ; Female ; Humans ; Multiple Carboxylase Deficiency ; genetics ; Mutation ; Open Reading Frames ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Sequence Analysis, DNA

OBJECTIVE: To provide genetic testing for two brothers with mental retardation and epilepsy. METHODS: Array comparative genomic hybridization (aCGH) was used to detect copy number variations in the two patients, their parents and maternal grandparents. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was utilized to delineate the deleted region in the pedigree. RESULTS: A 138 kb deletion in 15q11.2 region was detected by aCGH in both patients, which encompassed part of the UBE3A gene. MS-MLPA has narrowed down the region to exons 8 to 14 of the UBE3A gene. The same deletion was also found in their mother and grandfather. CONCLUSION The pathogenesis of this rare form of recurrent Angelman syndrome may be attributed to the partial deletion of maternal UBE3A gene.
Angelman Syndrome ; Comparative Genomic Hybridization ; DNA Copy Number Variations ; Female ; Gene Deletion ; Humans ; Male ; Sequence Deletion ; Ubiquitin-Protein Ligases

OBJECTIVE: To explore the genetic basis for a Chinese pedigree where three siblings were affected with Parkinson's disease. METHODS: Multiple ligation-dependent probe amplification (MLPA) and next-generation sequencing (NGS) were employed to detect the causative mutation. Sanger sequencing of cDNA was also used for verify the effect of mutation on the transcription of RNA. RESULTS: Heterozygous deletion of exon 3 of the PARK2 gene was detected by MLPA, while a heterozygous splice site variant c.619-3G>C was detected by NGS. Both mutations were shown to result in aberrant transcripts of the PARK2 gene (loss of exons 3 and 6, respectively) by Sanger sequencing of cDNA. Both mutations have co-segregated with the disease in the pedigree. CONCLUSION Compound heterozygous mutations of the PARK2 gene probably underlie the disease in this pedigree. Identification of the splice site variant c.619-3G>C has expanded the mutation spectrum of the PARK2 gene.
Asian Continental Ancestry Group ; China ; DNA Mutational Analysis ; Exons ; Heterozygote ; Humans ; Mutation ; Parkinson Disease ; genetics ; Pedigree ; Ubiquitin-Protein Ligases ; genetics

DNA damage response (DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modifications play an important role in DDR, from signaling DNA damage to mediating DNA repair. In this report, we found that the E3 ligase ring finger protein 126 (RNF126) was recruited to UV laser micro-irradiation-induced stripes in a RNF8-dependent manner. RNF126 directly interacted with and ubiquitinated another E3 ligase, RNF168. Overexpression of wild type RNF126, but not catalytically-inactive mutant RNF126 (CC229/232AA), diminished ubiquitination of H2A histone family member X (H2AX), and subsequent bleomycin-induced focus formation of total ubiquitin FK2, TP53-binding protein 1 (53BP1), and receptor-associated protein 80 (RAP80). Interestingly, both RNF126 overexpression and RNF126 downregulation compromised homologous recombination (HR)-mediated repair of DNA double-strand breaks (DSBs). Taken together, our findings demonstrate that RNF126 negatively regulates RNF168 function in DDR and its appropriate cellular expression levels are essential for HR-mediated DSB repair.
Carrier Proteins ; metabolism ; Cell Line, Tumor ; DNA Breaks, Double-Stranded ; DNA Repair ; genetics ; DNA-Binding Proteins ; metabolism ; Genomic Instability ; HeLa Cells ; Histones ; metabolism ; Humans ; Nuclear Proteins ; metabolism ; RNA Interference ; RNA, Small Interfering ; genetics ; Signal Transduction ; Tumor Suppressor p53-Binding Protein 1 ; metabolism ; Ubiquitin ; Ubiquitin-Protein Ligases ; genetics ; metabolism ; Ubiquitination