1.Research progress on the molecular genetic mechanism of Parkinson's disease.
Chinese Journal of Medical Genetics 2026;43(2):151-157
The pathogenesis of Parkinson's disease is closely related to genetic factors. This article has systematically reviewed the research progress of molecular genetic mechanism on Parkinson's disease by focusing on the role of six high-penetrance pathogenic genes (SNCA, LRRK2, PRKN, PINK1, PARK7, and VPS35) and some risk genes (such as GBA1). These genetic variants eventually converge in three core pathogenic biological pathways, including lysosomal-autophagy pathway disorder, mitochondrial quality control disorder and α-synuclein metabolic abnormality. In-depth understanding of these molecular mechanisms is of great significance for the development of targeted therapy and realization of precision medicine for this disease.
Humans
;
Parkinson Disease/metabolism*
;
alpha-Synuclein/genetics*
;
Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics*
;
Genetic Predisposition to Disease
;
Protein Kinases/genetics*
;
Animals
;
Glucosylceramidase/genetics*
;
Ubiquitin-Protein Ligases/genetics*
2.NIP7 upregulates the expression of ubiquitin-conjugating enzyme E2 C to promote tumor growth in anaplastic thyroid cancer.
Yingying GONG ; Ziwen FANG ; Yixuan WANG ; Minghua GE ; Zongfu PAN
Journal of Zhejiang University. Medical sciences 2025;54(3):372-381
OBJECTIVES:
To investigate the role of nucleolar pre-rRNA processing protein NIP7 (NIP7) in maintaining the malignant phenotype of anaplastic thyroid cancer (ATC) and its molecular mechanisms.
METHODS:
NIP7 expression in ATC tissues and its gene knock-out effects in ATC cells were analyzed using gene expression microarray (GSE33630), proteome database (IPX0008941000) and the Dependency Map database, respectively. Expression and localization of NIP7 in normal thyroid cells, papillary thyroid cancer cells, and ATC cells were detected by Western blotting. Small interfering RNA (siRNA) was transfected into ATC cells, and the knockdown efficiency of NIP7 was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blotting. Cell proliferation was assessed by CCK-8 assay, colony formation was evaluated by colony formation assay, and tumor growth was assessed by xenograft tumor model in nude mice. SUnSET (surface sensing of translation) assay combined with co-immunoprecipitation were employed to evaluate the effect of NIP7 silencing on ubiquitin-conjugating enzyme E2 C (UBE2C) translation. Finally, gene set enrichment analysis was used to identify shared pathways of NIP7 and UBE2C, which were validated by qRT-PCR.
RESULTS:
Compared with normal tissues and papillary thyroid cancer, NIP7 was significantly upregulated in ATC tissues, and had a gene knock-out fitness effect on different ATC cell lines. The relative protein levels of NIP7 in ATC cells were significantly higher than those in normal thyroid follicular cells, and the protein was mainly expressed in the nucleus. NIP7 silencing significantly inhibited cell proliferation and reduced colony formation. Xenograft tumor model showed that NIP7 knockdown significantly slowed down the growth of ATC xenograft, and the tumor volume and weight were significantly lower than those in the control group (all P<0.05). NIP7 silencing downregulated the protein level of UBE2C, but did not affect the expression of UBE2C mRNA. Compared to the control group, UBE2C silencing significantly inhibited ATC cells proliferation (P<0.01) and colony formation (P<0.05). UBE2C overexpression reversed the proliferation-inhibitory effect induced by NIP7 silencing (P<0.01). Gene set enrichment analysis indicated that NIP7 and UBE2C were both involved in DNA replication. NIP7 or UBE2C silencing could significantly downregulate the expression levels of DNA polymerase epsilon, catalytic subunit 2 and replication factor C4 in DNA replication pathway.
CONCLUSIONS
NIP7 promotes ATC tumor growth by upregulating UBE2C to mediate DNA replication.
Humans
;
Ubiquitin-Conjugating Enzymes/genetics*
;
Thyroid Neoplasms/genetics*
;
Thyroid Carcinoma, Anaplastic/genetics*
;
Animals
;
Mice, Nude
;
Mice
;
Cell Line, Tumor
;
Cell Proliferation
;
Up-Regulation
;
RNA, Small Interfering/genetics*
;
Nuclear Proteins/metabolism*
;
Gene Expression Regulation, Neoplastic
3.Latest Research Progress of E3 Ubiquitin Ligase in the Diagnosis and Treatment of Acute Myeloid Leukemia --Review.
Wei-Lin LIU ; Chun-Yi LYU ; Teng WANG ; Chen HAN ; Rui-Rong XU
Journal of Experimental Hematology 2025;33(5):1542-1545
E3 ubiquitin ligase is a key enzyme that determines substrate specificity during ubiquitination and plays an important role in regulating the degradation of tumor suppressor or oncogenic proteins. E3 ubiquitin ligase is involved in regulating leukemia cell differentiation, cell cycle and immune response, and it is closely related to the occurrence and development of acute myeloid leukemia (AML). Targeting highly specific E3 ubiquitin ligase can be used as an effective treatment for AML. This article reviewed the latest progress of E3 ubiquitin ligase in the diagnosis and treatment of AML, aiming to provide insights for the precise targeted therapy of this disease.
Humans
;
Ubiquitin-Protein Ligases/metabolism*
;
Leukemia, Myeloid, Acute/therapy*
4.Role and mechanism of ubiquitin-specific protease 35 in ferroptosis of rheumatoid arthritis-fibroblast like synoviocytes.
Lianghua FENG ; Lirong HONG ; Yujia CHEN ; Xueming CAI
Journal of Peking University(Health Sciences) 2025;57(5):919-925
OBJECTIVE:
To elucidate the role and underlying mechanism of ubiquitin-specific protease 35 (USP35) in ferroptosis of rheumatoid arthritis-fibroblast like synoviocytes (RA-FLS), thereby enhancing our comprehension of the pathogenesis of RA and identifying potential therapeutic targets for its treatment.
METHODS:
(1) RA-FLS were cultured in vitro and transduced with lentiviral vectors to establish stable cell lines: A USP35-knockdown line (short hairpin ribonucleic acid of USP35, shUSP35) and its control (negtive control of short hairpin ribonucleic acid, shNC), as well as a overexpression of USP35 line (USP35 OE) and its control (Vector). To investigate the role of USP35 in ferroptosis regulation, a ferroptosis model was induced in RA-FLS by treatment with 1 μmol/L Erastin. The cells were divided into six groups: shNC, shNC + Erastin, shUSP35 + Erastin, Vector, Vector + Erastin, and USP35 OE + Erastin. (2) Cell viability was detected using the cell counting kit-8 (CCK-8). (3) Reactive oxygen species (ROS), malondialdehyde (MDA), glutathione/glutathione disulfide (GSH/GSSG) ratios, and Ferrous ion (Fe2+) levels were measured using specific assay kits to evaluate oxidative stress, lipid peroxidation, and glutathione redox status in the cells. (4) Protein expression levels of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) were detected using Western blotting to investigate their potential involvement in USP35-mediated ferroptosis regulation.
RESULTS:
(1) Compared with the shNC +Erastin group, the cell viability of the shUSP35+Erastin group was significantly decreased (P < 0.001), while it was notably increased in the USP35 OE+Erastin group compared with the Vector+Erastin group (P < 0.001). These findings indicated that USP35 could alleviate the inhibitory effect of Erastin on RA-FLS cell viability. (2) In comparison to the shNC+Erastin group, the levels of ROS (P < 0.001), MDA (P < 0.05), and Fe2+ (P < 0.001) were significantly elevated, and the GSH/GSSG ratio was increased (P < 0.05) in the shUSP35+Erastin group. Conversely, the levels of ROS (P < 0.001), MDA (P < 0.05), and Fe2+ (P < 0.05) were significantly decreased, and the GSH/GSSG ratio was decreased (P < 0.05) in the USP35 OE+Erastin group compared with the Vector+Erastin group. These results suggested that USP35 could inhibit Erastin-induced oxidative stress and lipid peroxidation in RA-FLS. (3) In Erastin-induced RA-FLS, the expression of USP35 was positively correlated with the protein levels of SLC7A11 and GPX4, indicating a potential mechanism by which USP35 regulated ferroptosis in these cells.
CONCLUSION
USP35 inhibits ferroptosis in RA-FLS, potentially through the increased expression of SLC7A11 and GPX4.
Ferroptosis
;
Humans
;
Arthritis, Rheumatoid/metabolism*
;
Synoviocytes/pathology*
;
Reactive Oxygen Species/metabolism*
;
Ubiquitin-Specific Proteases/metabolism*
;
Fibroblasts/pathology*
;
Cell Survival
;
Piperazines/pharmacology*
;
Endopeptidases/metabolism*
;
Cells, Cultured
;
Cell Line
;
Amino Acid Transport System y+
5.Effect of Bushen Huoxue Granule on Clearance of Pathological α-Synuclein in MPP+-Induced PC12 Cells.
Zhen-Xian LUAN ; Xiang-Lin TANG ; Fei-Ran HAO ; Min LI ; Shao-Dan LI ; Ming-Hui YANG
Chinese journal of integrative medicine 2025;31(9):830-836
OBJECTIVE:
To investigate the effects of Bushen Huoxue Granule on the ubiquitin-proteasome system (UPS) in an in vitro model of Parkinson's disease.
METHODS:
After treated with 1-methyl-4-phenylpyridinium (MPP+, 1 mmol/L) for 24 h, the cells were incubated with drug-free serum, Madopar-containing serum or Bushen Huoxue Granule-containing serum (BCS, 5%, 10%, and 20%) for another 24 h. The levels of α-synuclein (α-syn), tyrosine hydroxylase (TH) and UPS-related proteins were detected by Western blot. The expression levels of α-syn in PC12 cells were also analyzed by Western blot after treated with proteasome inhibitor MG132 and WT-α-syn plasmid transfection, respectively, as well as the alterations induced by subsequent BCS intervention. Immunocytochemistry was performed to determine the changes in α-syn phosphorylation at serine 129 (pSer129-α-syn) expression. The 20S proteasome levels were measured by enzyme-linked immunosorbnent assay.
RESULTS:
BCS (volume fraction ⩽20%) intervention could alleviate the MMP+-induced cell viability decrease (P<0.05). In the MPP+ treated cells, α-syn was up-regulated, while TH and proteins of UPS such as ubiquitin (Ub), Ub binding with Ub-activating enzyme (UBE1), Parkin and Ub C-terminal hydrolase-1 (UCHL-1) were down-regulated (P<0.05). BCS intervention could attenuate the above changes (P<0.05). The activity of BCS on blocking α-syn accumulation was weakened by MG132 (P<0.05). While α-syn level was significantly increased in cells transfected with plasmid, and reduced by BCS intervention (P<0.05). pSer129-α-syn was increased in MPP+-induced PC12 cells, whereas decreased by later BCS intervention (P<0.05). The 20S proteasome activity of MPP+-induced PC12 cells was decreased, but increased after BCS intervention (P<0.05).
CONCLUSION
BCS intervention protected UPS function, increased 20S proteasome activity, promoted pathological α-syn clearance, restored cell viability, and reversed the damage caused by MPP+ in the in vitro model of Parkinson's disease.
PC12 Cells
;
alpha-Synuclein/metabolism*
;
Rats
;
Animals
;
1-Methyl-4-phenylpyridinium/toxicity*
;
Proteasome Endopeptidase Complex/metabolism*
;
Drugs, Chinese Herbal/pharmacology*
;
Ubiquitin/metabolism*
;
Cell Survival/drug effects*
;
Phosphorylation/drug effects*
;
Tyrosine 3-Monooxygenase/metabolism*
6.A quinolinyl analog of resveratrol improves neuronal damage after ischemic stroke by promoting Parkin-mediated mitophagy.
Qingqi MENG ; Yan MI ; Libin XU ; Yeshu LIU ; Dong LIANG ; Yongping WANG ; Yan WANG ; Yueyang LIU ; Guoliang CHEN ; Yue HOU
Chinese Journal of Natural Medicines (English Ed.) 2025;23(2):214-224
Ischemic stroke (IS) is a prevalent neurological disorder often resulting in significant disability or mortality. Resveratrol, extracted from Polygonum cuspidatum Sieb. et Zucc. (commonly known as Japanese knotweed), has been recognized for its potent neuroprotective properties. However, the neuroprotective efficacy of its derivative, (E)-4-(3,5-dimethoxystyryl) quinoline (RV02), against ischemic stroke remains inadequately explored. This study aimed to evaluate the protective effects of RV02 on neuronal ischemia-reperfusion injury both in vitro and in vivo. The research utilized an animal model of middle cerebral artery occlusion/reperfusion and SH-SY5Y cells subjected to oxygen-glucose deprivation and reperfusion to simulate ischemic conditions. The findings demonstrate that RV02 attenuates neuronal mitochondrial damage and scavenges reactive oxygen species (ROS) through mitophagy activation. Furthermore, Parkin knockdown was found to abolish RV02's ability to activate mitophagy and neuroprotection in vitro. These results suggest that RV02 shows promise as a neuroprotective agent, with the activation of Parkin-mediated mitophagy potentially serving as the primary mechanism underlying its neuroprotective effects.
Animals
;
Ubiquitin-Protein Ligases/genetics*
;
Mitophagy/drug effects*
;
Resveratrol/analogs & derivatives*
;
Neuroprotective Agents/pharmacology*
;
Humans
;
Neurons/metabolism*
;
Reactive Oxygen Species/metabolism*
;
Ischemic Stroke/genetics*
;
Male
;
Quinolines/pharmacology*
;
Mice
;
Fallopia japonica/chemistry*
;
Mitochondria/metabolism*
;
Reperfusion Injury/metabolism*
;
Rats
;
Mice, Inbred C57BL
;
Disease Models, Animal
7.Effects of electroacupuncture on mitochondrial autophagy and Sirt1/FOXO3/PINK1/Parkin pathway in rats with learning-memory impairment after cerebral ischemia reperfusion injury.
Kaiqi SU ; Zhuan LV ; Ming ZHANG ; Lulu CHEN ; Hao LIU ; Jing GAO ; Xiaodong FENG
Chinese Acupuncture & Moxibustion 2025;45(2):193-199
OBJECTIVE:
To observe the effects of electroacupuncture (EA) at "Shenting" (GV24) and "Baihui" (GV20) on mitochondrial autophagy in hippocampal neurons and silent information regulator sirtuin 1 (Sirt1)/forkhead box O3 (FOXO3)/PTEN-inducible kinase 1 (PINK1)/Parkin pathway in rats with learning-memory impairment after cerebral ischemia reperfusion injury.
METHODS:
A total of 35 male SD rats were randomly divided into a sham operation group (9 rats) and a modeling group (26 rats). In the modeling group, middle cerebral artery occlusion method was used to establish the middle cerebral artery ischemia-reperfusion (MCAO/R) model, and 18 rats of successful modeling were randomly divided into a model group and an EA group, 9 rats in each one. EA was applied at "Shenting" (GV24) and "Baihui" (GV20) in the EA group, 30 min a time, once a day for 14 days. After modeling and on 7th and 14th days of intervention, neurologic deficit score was observed; the learning-memory ability was detected by Morris water maze test; the morphology of neurons in CA1 area of hippocampus was detected by Nissl staining; the mitochondrial morphology was observed by transmission electron microscopy; the protein expression of Beclin-1, microtubule-associated protein 1 light chain 3B (LC3B), P62, Sitrt1, FOXO3, PINK1 and Parkin was detected by Western blot.
RESULTS:
After modeling, the neurologic deficit scores in the model group and the EA group were higher than that in the sham operation group (P<0.001); on 7th and 14th days of intervention, the neurologic deficit scores in the model group were higher than those in the sham operation group (P<0.001), the neurologic deficit scores in the EA group were lower than those in the model group (P<0.05, P<0.01). After modeling, the escape latency in the model group and the EA group was prolonged compared with that in the sham operation group (P<0.001); on 9th-13th days of intervention, the escape latency in the model group was prolonged compared with that in the sham operation group (P<0.001), the escape latency in the EA group was shortened compared with that in the model group (P<0.05, P<0.01, P<0.001). The number of crossing plateau in the model group was less than that in the sham operation group (P<0.001); the number of crossing plateau in the EA group was more than that in the model group (P<0.05). In the model group, in CA1 area of hippocampus, the number of neurons was less, with sparse arrangement, nuclear fixation, deep cytoplasmic staining, and reduction of Nissl substance; the morphology of mitochondrion was swollen, membrane structure was fragmented, and autophagic lysosomes were formed. Compared with the model group, in the EA group, in CA1 area of hippocampus, the number of neurons was increased, the number of cells of abnormal morphology was decreased, and the number of Nissl substance was increased; the morphology of mitochondrion was more intact and the number of autophagic lysosomes was increased. Compared with the sham operation group, in the model group, the protein expression of Beclin-1, FOXO3, PINK1, Parkin and the LC3BⅡ/Ⅰ ratio in hippocampus were increased (P<0.01, P<0.001), while the protein expression of P62 was decreased (P<0.05). Compared with the model group, in the EA group, the protein expression of Beclin-1, Sirt1, FOXO3, PINK1, Parkin and the LC3BⅡ/Ⅰratio in hippocampus were increased (P<0.001, P<0.01), while the protein expression of P62 was decreased (P<0.001).
CONCLUSION
EA at "Shenting" (GV24) and "Baihui" (GV20) can relieve the symptoms of neurological deficits and improve the learning-memory ability in MCAO/R rats, its mechanism may relate to the modulation of Sirt1/FOXO3/PINK1/Parkin pathway and the enhancement of mitochondrial autophagy.
Animals
;
Electroacupuncture
;
Male
;
Rats, Sprague-Dawley
;
Rats
;
Forkhead Box Protein O3/genetics*
;
Reperfusion Injury/metabolism*
;
Ubiquitin-Protein Ligases/genetics*
;
Brain Ischemia/complications*
;
Mitochondria/genetics*
;
Autophagy
;
Protein Kinases/genetics*
;
Sirtuin 1/genetics*
;
Humans
;
Memory Disorders/psychology*
;
Signal Transduction
8.Effect of acupuncture pretreatment on PINK1/Parkin pathway-mediated mitophagy in rats with exercise-induced muscle damage.
Yulin GUO ; Ming GAO ; Huan CHEN ; Hui LI ; Xun TIAN ; Yuan ZHAO ; Gang XU ; Junling WEN ; Shaoxiong LI
Chinese Acupuncture & Moxibustion 2025;45(11):1617-1626
OBJECTIVE:
Based on the PTEN-induced hypothetical kinase 1 (PINK1)/Parkin pathway, the effect of acupuncture pretreatment on the expression of mitochondrial autophagy-related proteins in gastrocnemius muscle tissue of rats with exercise-induced muscle damage (EIMD) was observed, and the underlying mechanism of acupuncture pretreatment for the prevention and treatment of EIMD was explored.
METHODS:
Of 88 SD male rats, aged 6 weeks, 8 rats were randomly selected as a blank group, and the remaining 80 rats were randomized into a model group and an acupuncture pretreatment group, with 40 rats in each group. Either the model group or the acupuncture pretreatment group was subdivided randomly into 5 subgroups with 8 rats in each one according to the time points of sample collection, 0 h, 12 h, 24 h, 48 h and 72 h after modeling. An intermittent downhill running centrifugal exercise was carried out on an animal experimental treadmill to establish the EIMD model in the model group and the acupuncture pretreatment group. The rats in the acupuncture pretreatment group received acupuncture at "Guanyuan" (CV6) and bilateral "Zusanli" (ST36), once a day for 20 min each time, for 7 consecutive days before EIMD model preparation. Transmission electron microscopy was used to observe the ultrastructure of gastrocnemius muscle tissue in each group. The contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in serum were detected by ELISA. Western blot was used to detect the protein expression of PINK1, Parkin, sequestosome 1 (p62) and microtubule-associated protein light chain 3B (LC3B) in rat gastrocnemius muscle tissue. Real-time PCR was adopted to detect the mRNA expression of PINK1, Parkin, p62 and LC3B in rat gastrocnemius muscle tissue.
RESULTS:
Compared with the blank group, the mitochondria of gastrocnemius muscles showed obvious swelling in the 0 h, 12 h, 24 h, and 48 h model subgroups , autophagosomes were formed in the 12 h and 24 h model subgroups, and the mitochondrial morphology returned to normal gradually in the 72 h model subgroup. The serum MDA contents of rats in 5 model subgroups increased (P<0.01, P<0.05). The contents of SOD and CAT in the subgroups of 0 h, 12 h, 24 h and 48 h decreased (P<0.05, P<0.01). The protein and mRNA expression levels of PINK1, Parkin and LC3B in gastrocnemius muscle tissue of rats in 0 h, 12 h and 24 h subgroups were elevated (P<0.01); and the protein and mRNA expression levels of p62 in the 0 h, 12 h, 24 h and 48 h subgroups were reduced (P<0.01, P<0.05). Compared with the model subgroup at the same time point, the myofibril damage and the degree of mitochondrial swelling were mild in each acupuncture pretreatment subgroup, and the numbers of autophagosomes were fewer. The contents of MDA in the acupuncture pretreatment subgroups decreased at 0 h, 12 h, 24 h, and 48 h (P<0.05, P<0.01). The contents of SOD and CAT in the 12 h acupuncture pretreatment subgroup increased (P<0.05, P<0.01). The protein and mRNA expression levels of PINK1 and Parkin in the 0 h, 12 h, and 24 h acupuncture pretreatment subgroups decreased (P<0.01, P<0.05). The protein and mRNA expression levels of LC3B in the 12 h acupuncture pretreatment subgroup decreased (P<0.01), and that of p62 in the 0 h and 24 h acupuncture pretreatment subgroups increased (P<0.01, P<0.05).
CONCLUSION
The intermittent downhill running centrifugal exercise induces the excessive mitochondrial autophagy. Acupuncture pretreatment may attenuate EIMD, and the underlying mechanism is related to the regulation of PINK1/Parkin signaling pathway expression, reducing oxidative stress damage in skeletal muscle cells, and inhibiting mitochondrial autophagy overactivation.
Animals
;
Ubiquitin-Protein Ligases/genetics*
;
Male
;
Rats
;
Acupuncture Therapy
;
Protein Kinases/genetics*
;
Rats, Sprague-Dawley
;
Mitophagy
;
Humans
;
Muscle, Skeletal/metabolism*
;
Physical Conditioning, Animal
;
Muscular Diseases/physiopathology*
;
Signal Transduction
9.Clinical feature and genetic analysis of a child with X-linked Opitz G/BBB syndrome caused by nonsense variant in the MID1 gene mediated by mRNA degradation escape.
Yingyu YAN ; Li HE ; Ying YANG ; Duan WANG ; Haiqing ZHANG ; Yanni CHEN
Chinese Journal of Medical Genetics 2025;42(2):219-225
OBJECTIVE:
To explore the genotype-phenotype relationship in a child with Opitz G/BBB syndrome (OS) with mild clinical phenotype.
METHODS:
A child with motor developmental delay as the initial symptom admitted to Xi'an Children's Hospital on June 10, 2021 was selected for this study. Clinical data were collected, and peripheral blood samples were obtained from the child and his mother. Whole exome sequencing (WES) was performed to identify genetic variant in the child. Candidate variant were verified by Sanger sequencing to assess inheritance patterns and pathogenicity. Real-time fluorescence quantitative PCR (RT-qPCR) and Western blot (WB) analyses were conducted to evaluate the effects of the variant on mRNA and protein expression, respectively, using recombinant expression plasmids generated in vitro. This study was approved by the Medical Ethics Committee of Xi'an Children's Hospital (Ethics No. 20240045).
RESULTS:
The child, a 9-month-and-7-day-old boy, presented with a low nasal bridge, hypertelorism, and difficulty sitting independently. Echocardiography revealed an atrial septal defect. WES identified a homozygous variant in the MIDI gene, c.1483C>T (p.R495X), which was confirmed by Sanger sequencing and found to be inherited from the mother.Recombinant expression plasmids were successfully constructed. RT-qPCR analysis showed that the variant significantly reduced MIDI gene mRNA expression, while WB results indicated that the variant led to the production of a truncated protein.
CONCLUSION
The mild clinical phenotype of OS in this child may be attributed to the mRNA degradation escape mechanism induced by the nonsense variant c.1483C>T (p.R495X) in the MIDI gene. These findings provide valuable diagnostic insights for this pedigree and contribute to the understanding of the genotype-phenotype correlation in OS.
Humans
;
Male
;
Infant
;
Transcription Factors/metabolism*
;
Microtubule Proteins/genetics*
;
Craniosynostoses/genetics*
;
Hypospadias/genetics*
;
Codon, Nonsense/genetics*
;
RNA, Messenger/metabolism*
;
Female
;
RNA Stability/genetics*
;
Phenotype
;
Nuclear Proteins/genetics*
;
Ubiquitin-Protein Ligases
;
Esophagus/abnormalities*
;
Hypertelorism
10.N-terminal domain of Rep encoded by beet severe curly top virus mediates suppression of RNA silencing and induces VIM5 expression.
Jingyu XU ; Jianxin LU ; Zhenyu YU ; Meijie HU ; Chengkai GUO ; Zhongqi QIU ; Zhongqi CHEN
Chinese Journal of Biotechnology 2025;41(10):3956-3968
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*

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