T7 RNA polymerase (T7 RNAP) is one of the simplest known RNA polymerases. Its unique structural features make it a critical model for studying the mechanisms of RNA synthesis. This review systematically examines the static crystal structure of T7 RNAP, beginning with an in-depth examination of its characteristic “thumb”, “palm”, and “finger” domains, which form the classic “right-hand-like” architecture. By detailing these structural elements, this review establishes a foundation for understanding the overall organization of T7 RNAP. This review systematically maps the functional roles of secondary structural elements and their subdomains in transcriptional catalysis, progressively elucidating the fundamental relationships between structure and function. Further, the intrinsic flexibility of T7 RNAP and its applications in research are also discussed. Additionally, the review presents the structural diagrams of the enzyme at different stages of the transcription process, and through these diagrams, it provides a detailed description of the complete transcription process of T7 RNAP. By integrating structural dynamics and kinetics analyses, the review constructs a comprehensive framework that bridges static structure to dynamic processes. Despite its advantages, T7 RNAP has a notable limitation: it generates double-stranded RNA (dsRNA) as a byproduct. The presence of dsRNA not only compromises the purity of mRNA products but also elicits nonspecific immune responses, which pose significant challenges for biotechnological and therapeutic applications. The review provides a detailed exploration of the mechanisms underlying dsRNA formation during T7 RNAP catalysis, reviews current strategies to mitigate this issue, and highlights recent progress in the field. A key focus is the semi-rational design of T7 RNAP mutants engineered to minimize dsRNA generation and enhance catalytic performance. Beyond its role in transcription, T7 RNAP exhibits rapid development and extensive application in fields, including gene editing, biosensing, and mRNA vaccines. This review systematically examines the structure-function relationships of T7 RNAP, elucidates the mechanisms of dsRNA formation, and discusses engineering strategies to optimize its performance. It further explores the engineering optimization and functional expansion of T7 RNAP. Furthermore, this review also addresses the pressing issues that currently need resolution, discusses the major challenges in the practical application of T7 RNAP, and provides an outlook on potential future research directions. In summary, this review provides a comprehensive analysis of T7 RNAP, ranging from its structural architecture to cutting-edge applications. We systematically examine: (1) the characteristic right-hand domains (thumb, palm, fingers) that define its minimalistic structure; (2) the structure-function relationships underlying transcriptional catalysis; and (3) the dynamic transitions during the complete transcription cycle. While highlighting T7 RNAP’s versatility in gene editing, biosensing, and mRNA vaccine production, we critically address its major limitation—dsRNA byproduct formation—and evaluate engineering solutions including semi-rationally designed mutants. By synthesizing current knowledge and identifying key challenges, this work aims to provide novel insights for the development and application of T7 RNAP and to foster further thought and progress in related fields.

Cellulose synthase (CesA), one of the key enzymes in the biosynthesis of cellulose in plants, plays an important role in plant growth and plant resistance. In this study, a total of 21 AsCesA genes from Aquilaria sinensis were systematically identified and the physico-chemical characteristics were analyzed based on genome database and bioinformatical methods. The phylogenetic tree was constructed and the gene location on chromosome, cis-acting elements in the 2 000 basepairs upstream regulatory regions and conservative motifs were analyzed. The AsCesA proteins were mainly located on the plasma membrane. The number of amino acids of the proteins ranged from 390 to 1 261. The isoelectric point distributed from 5.67 to 8.86. All of the 21 AsCesA proteins possessed the transmembrane domains, the number of which was from 6 to 8. The genes were classified into 3 groups according to the phylogenetic relationship. Obvious differences were observed in motif composition in genes from different groups. However, motif2, motif6, motif7 and motif10 were observed in all of AsCesA proteins. Analysis of cis-acting elements indicated that AsCesA genes family has cis-acting elements related to plant hormones, abiotic stresses, and biological processes. Seven AsCesA genes with differential expression were selected according to the calli transcriptome data induced by NaCl at different times and their expression levels under different abiotic stresses were analyzed by quantitative real-time PCR. The results indicated that salt, low temperature, drought, and heavy metal stresses could affect the expression level of AsCesA genes, and the abundance of AsCesA1, AsCesA3 and AsCesA20 showed a significant change, implying their potential important roles to the abiotic stresses. The accumulation pattern of cellulose content under different abiotic stresses was similar to the expression trend of AsCesA genes. Our results provide valuable insights into the role of cellulose synthase in A.sinensis in plant defense.

Objective To evaluate the characteristics of the mass balance and pharmacokinetics of[14 C]birociclib in Chinese male healthy volunteers after a single oral administration.Methods This study used a 14 C labeled method to investigate the mass balance and biological transformation of birociclib in human.Subjects were given a single oral dose of 360 mg/50 pCi of[14 C]birociclib suspension after meals.The blood,urine,and fecal samples were collected at specified time points/intervals after administration.The radiation levels of 14 C labeled birociclib-related compounds in the blood,plasma,urine,and feces were analyzed using liquid scintillation counting.In addition,a combination of high-performance liquid chromatography and on-line/off-line isotope detectors was used to obtain radioactive isotope metabolite spectra of plasma,urine,and fecal samples,and high-resolution mass spectrometry was used to identify the main metabolites.Results A total of 6 healthy male subjects were enrolled in this study.The median peak time of radioactive components in plasma was 5.00 h and the average terminal elimination half-life was 43.70 h after administration.The radioactive components were basically excreted and cleared from the body within 288.00 hours after administration,and average cumulative recovery rate of radioactive drugs was(94.10±8.19)％.The radioactive drugs were mainly excreted through feces,accounting for(84.60±7.10)％of the dose of radioactive drugs administered.Urine was the secondary excretory pathway,accounting for 9.41％of the dose of radioactive drugs administered.Metabolic analysis indicated that the prototype drug was the main radioactive components in plasma samples.The main metabolites in plasma were RM4(XZP-5286),RM6(XZP-3584),and RM7(XZP-5736).The drugs were mainly cleared from the body in the form of prototype drugs and metabolites.In addition to prototype drugs,a total of 9 metabolites were identified and analyzed in plasma,urine,and fecal samples,all of which were phase 1 metabolites.The main metabolic and clearance pathways of drugs in the body were deethylation,diisopropylat ion,oxidation,etc.Conclusion After a single oral administration of[14C]birociclib suspension to healthy subjects,it was mainly cleared from the body in the form of prototype drugs and metabolites,with feces as the main excretory pathway and urine as the secondary excretory pathway.Drugs mainly undergo metabolic reactions in the body,such as deethylation,diisopropylation,and oxidation.The subjects were well tolerance after administration.

Objective This study aimed to evaluate whether the onset of the plateau phase of slow hepatitis B surface antigen decline in patients with chronic hepatitis B treated with intermittent interferon therapy is related to the frequency of dendritic cell subsets and expression of the costimulatory molecules CD40,CD80,CD83,and CD86. Method This was a cross-sectional study in which patients were divided into a natural history group(namely NH group),a long-term oral nucleoside analogs treatment group(namely NA group),and a plateau-arriving group(namely P group).The percentage of plasmacytoid dendritic cell and myeloid dendritic cell subsets in peripheral blood lymphocytes and monocytes and the mean fluorescence intensity of their surface costimulatory molecules were detected using a flow cytometer. Results In total,143 patients were enrolled(NH group,n = 49;NA group,n = 47;P group,n = 47).The results demonstrated that CD141/CD1c double negative myeloid dendritic cell(DNmDC)/lymphocytes and monocytes(%)in P group(0.041[0.024,0.069])was significantly lower than that in NH group(0.270[0.135,0.407])and NA group(0.273[0.150,0.443]),and CD86 mean fluorescence intensity of DNmDCs in P group(1832.0[1484.0,2793.0])was significantly lower than that in NH group(4316.0[2958.0,5169.0])and NA group(3299.0[2534.0,4371.0]),Adjusted P all<0.001. Conclusion Reduced DNmDCs and impaired maturation may be associated with the onset of the plateau phase during intermittent interferon therapy in patients with chronic hepatitis B.

Objective To explore characteristics of clinical parameters and cytokines in patients with drug-induced liver injury(DILI)caused by different drugs and their correlation with clinical indicators. Method The study was conducted on patients who were up to Review of Uncertainties in Confidence Assessment for Medical Tests(RUCAM)scoring criteria and clinically diagnosed with DILI.Based on Chinese herbal medicine,cardiovascular drugs,non-steroidal anti-inflammatory drugs(NSAIDs),anti-infective drugs,and other drugs,patients were divided into five groups.Cytokines were measured by Luminex technology.Baseline characteristics of clinical biochemical indicators and cytokines in DILI patients and their correlation were analyzed. Results 73 patients were enrolled.Age among five groups was statistically different(P=0.032).Alanine aminotransferase(ALT)(P=0.033)and aspartate aminotransferase(AST)(P=0.007)in NSAIDs group were higher than those in chinese herbal medicine group.Interleukin-6(IL-6)and tumor necrosis factor alpha(TNF-α)in patients with Chinese herbal medicine(IL-6:P<0.001;TNF-α:P<0.001)and cardiovascular medicine(IL-6:P=0.020;TNF-α:P=0.001)were lower than those in NSAIDs group.There was a positive correlation between ALT(r=0.697,P=0.025),AST(r=0.721,P=0.019),and IL-6 in NSAIDs group. Conclusion Older age may be more prone to DILI.Patients with NSAIDs have more severe liver damage in early stages of DILI,TNF-α and IL-6 may partake the inflammatory process of DILI.

Objective To explore the efficacy and safety of omalizumab in the treatment of allergic bronchopulmonary aspergillosis(ABPA).Methods The clinical data of 26 ABPA patients treated with omalizumab in Zhongshan Hospital,Fudan University from November 2018 to December 2023 and 24 ABPA patients treated with prednisone combined with itraconazole in the same period were analyzed retrospectively.The primary outcomes were exacerbation times and oral corticosteroid-sparing effect.The secondary outcomes were respiratory symptoms,circulating eosinophil count,total immunoglobin E(IgE)level,specific IgE for aspergillus,pulmonary function(the percentage value of forced expiratory volume in one second predicted[FEV1%pred]),fraction of exhaled nitric oxide(FeNO),thoracic computed tomography(CT)manifestation and adverse reactions.Results In omalizumab group,the exacerbation times of ABPA after 6 and 12 months of treatment were 0(0,0)times/6 months and 0(0,1)times/6 months,there was no significant difference(P=0.157),which were significantly lower than those of the baseline(1[1,2]times/6 months,P＜0.001).The oral dose of prednisone decreased from 10(5,15)mg/d(before treatment)to 3.125(0,5)mg/d(6 months after treatment,P＜0.001).After 12 months of treatment,the oral dose of prednisone was 0(0,3.125)mg/d,which was significantly lower than that of the baseline dose(P=0.003).After treatment with omalizumab for 12 months,the FeNO level decreased significantly(26[13,36]×10﹣9 vs 30[18,56]×10﹣9,P=0.049).There was no significant difference in blood eosinophil count,total IgE level,specific IgE for aspergillus and FEV1%pred before and after omalizumab treatment.After 6 months of treatment with omalizumab,respiratory symptoms were relieved in 23 patients(88.5%)and radiographic improvement was achieved in eight out of sixteen patients(50%)with mucus plugs.More patients successfully discontinued oral prednisone when treated with omalizumab for 12 months than those in control group(P=0.035).During the treatment of omalizumab,4(15.4%)patients had a slight increase in alanine aminotransferase(ALT),and 1 patient was complicated with hepatocellular carcinoma during follow-up.Conclusions Omazumab treatment can effectively reduce the number of acute episodes of ABPA,reduce the dosage of oral glucocorticoids,improve FeNO,facilitate the absorption of mucus plugs,and has high safety.

Objective:To analyze the clinical phenotype and genotypes of two children with Carnitine-acylcarnitine translocase deficiency (CACTD).Methods:Two children diagnosed with CACTD at the Gansu Provincial Maternal and Child Health Care Hospital respectively on January 3 and November 19, 2018 were selected as the study subjects. Trio-whole exome sequencing (trio-WES) was carried out, and candidate variants were validated through Sanger sequencing and pathogenicity analysis.Results:Both children were males and had manifested mainly with hypoglycemia. Trio-WES and Sanger sequencing showed that child 1 had harbored compound heterozygous variants of the SLC25A20 gene, namely c. 49G>C (p.Gly17Arg) and c. 106-2A>G, which were inherited from his father and mother, respectively. Child 2 had harbored homozygous c. 199-10T>G variants of the SLC25A20 gene, which were inherited from both of his parents. Among these, the c. 106-2A>G and c. 49G>C variants were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c. 49G>C (p.Gly17Arg), c. 106-2A>G, and c. 199-10T>G variants were classified as likely pathogenic (PM2_supporting+ PP3+ PM3_strong+ PP4), pathogenic (PVS1+ PM2_supporting+ PM5+ PP3), and pathogenic (PVS1+ PM2_supporting+ PP3+ PP5), respectively. Conclusion:Combined with their clinical phenotype and genetic analysis, both children were diagnosed with CACTD. Above finding has provided a basis for their treatment as well as genetic counseling and prenatal diagnosis for their families.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Objective To investigate the incidence rate,clinical characteristics,and prognosis of neonatal stroke in Shenzhen,China.Methods Led by Shenzhen Children's Hospital,the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022.The incidence,clinical characteristics,treatment,and prognosis of neonatal stroke in Shenzhen were analyzed.Results The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137,1/6 060,and 1/7 704,respectively.Ischemic stroke accounted for 75％(27/36);boys accounted for 64％(23/36).Among the 36 neonates,31(86％)had disease onset within 3 days after birth,and 19(53％)had convulsion as the initial presentation.Cerebral MRI showed that 22 neonates(61％)had left cerebral infarction and 13(36％)had basal ganglia infarction.Magnetic resonance angiography was performed for 12 neonates,among whom 9(75％)had involvement of the middle cerebral artery.Electroencephalography was performed for 29 neonates,with sharp waves in 21 neonates(72％)and seizures in 10 neonates(34％).Symptomatic/supportive treatment varied across different hospitals.Neonatal Behavioral Neurological Assessment was performed for 12 neonates(33％,12/36),with a mean score of(32±4)points.The prognosis of 27 neonates was followed up to around 12 months of age,with 44％(12/27)of the neonates having a good prognosis.Conclusions Ischemic stroke is the main type of neonatal stroke,often with convulsions as the initial presentation,involvement of the middle cerebral artery,sharp waves on electroencephalography,and a relatively low neurodevelopment score.Symptomatic/supportive treatment is the main treatment method,and some neonates tend to have a poor prognosis.

The effect of porcine SIRT5 on replication of foot and mouth disease virus type O(FMDV-O)and the underlying regulatory mechanism were investigated.Western blot and RT-qPCR analyses were employed to monitor expression of endoge-nous SIRT5 in PK-15 cells infected with FMDV-O.Three pairs of SIRT5-specific siRNAs were synthesized.Changes to SIRT5 and FMDV-O protein and transcript levels,in addition to virus copy numbers,were measured by western blot and RT-qPCR analyses.PK-15 cells were transfected with a eukaryotic SIRT5 expression plasmid.Western blot and RT-qPCR analyses were used to explore the impact of SIRT5 overexpression on FMDV-O replication.Meanwhile,RT-qPCR analysis was used to detect the effect of SIRT5 overexpression on the mRNA expression levels of type I interferon-stimulated genes induced by SeV and FMDV-O.The results showed that expression of SIRT5 was up-regulated in PK-15 cells infected with FMDV-O and siRNA interfered with SIRT5 to inhibit FMDV-O replication.SIRT5 overexpression promoted FMDV-O replication.SIRT5 over-expression decreased mRNA expression levels of interferon-stimulated genes induced by SeV and FMDV-O.These results suggest that FMDV-O infection stimulated expression of SIRT5 in PK-15 cells,while SIRT5 promoted FMDV-O rep-lication by inhibiting production of type I interferon-stimula-ted genes.These findings provide a reference to further ex-plore the mechanism underlying the ability of porcine SIRT5 to promote FMDV-O replication.