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.

BACKGROUND: Temozolomide (TMZ) resistance is a significant challenge in treating glioblastoma (GBM). Collagen remodeling has been shown to be a critical factor for therapy resistance in other cancers. This study aimed to investigate the mechanism of TMZ chemoresistance by GBM cells reprogramming collagens. METHODS: Key extracellular matrix components, including collagens, were examined in paired primary and recurrent GBM samples as well as in TMZ-treated spontaneous and grafted GBM murine models. Human GBM cell lines (U251, TS667) and mouse primary GBM cells were used for in vitro studies. RNA-sequencing analysis, chromatin immunoprecipitation, immunoprecipitation-mass spectrometry, and co-immunoprecipitation assays were conducted to explore the mechanisms involved in collagen accumulation. A series of in vitro and in vivo experiments were designed to assess the role of the collagen regulators prolyl 4-hydroxylase subunit alpha 1 (P4HA1) and yes-associated protein (YAP) in sensitizing GBM cells to TMZ. RESULTS: This study revealed that TMZ exposure significantly elevated collagen type I (COL I) expression in both GBM patients and murine models. Collagen accumulation sustained GBM cell survival under TMZ-induced stress, contributing to enhanced TMZ resistance. Mechanistically, P4HA1 directly binded to and hydroxylated YAP, preventing ubiquitination-mediated YAP degradation. Stabilized YAP robustly drove collagen type I alpha 1 ( COL1A1) transcription, leading to increased collagen deposition. Disruption of the P4HA1-YAP axis effectively reduced COL I deposition, sensitized GBM cells to TMZ, and significantly improved mouse survival. CONCLUSION P4HA1 maintained YAP-mediated COL1A1 transcription, leading to collagen accumulation and promoting chemoresistance in GBM.
Temozolomide ; Humans ; Glioblastoma/drug therapy* ; Animals ; Mice ; Cell Line, Tumor ; Drug Resistance, Neoplasm/genetics* ; YAP-Signaling Proteins ; Hydroxylation ; Dacarbazine/pharmacology* ; Adaptor Proteins, Signal Transducing/metabolism* ; Transcription Factors/metabolism* ; Collagen/biosynthesis* ; Collagen Type I/metabolism* ; Prolyl Hydroxylases/metabolism* ; Antineoplastic Agents, Alkylating/therapeutic use*

OBJECTIVES: To identify risk factors contributing to prolonged postoperative length of stay (LOS) in very elderly patients following hip fracture surgery, with a focus on postoperative complications and the impact of different anesthesia approaches. METHODS: This retrospective single-center cohort study enrolled patients aged 90 years or older who underwent hip fracture surgery at Peking Union Medical College Hospital between January 31, 2013 and December 31, 2023. Relevant perioperative data were collected. The primary outcome was postoperative LOS, and the study cohort was divided into two groups: postoperative LOS ≤ 7 days and LOS > 7 days. Logistic regression was performed to identify factors related to prolonged postoperative LOS. RESULTS: A total of 155 patients were included. The average age was 92.7 ± 2.6 years. There were 73 (47%) patients with postoperative LOS > 7 days. Postoperative pneumonia was the only factor associated with a prolonged postoperative LOS (OR = 2.12, 95% CI [1.09, 4.16], P = 0.028). Neither the type of anesthesia (regional vs. general anesthesia, OR = 1.00, 95% CI [0.53, 1.90], P = 0.993) nor the method of airway management (laryngeal mask ventilation vs. spontaneous breathing, OR = 1.46, 95% CI [0.58, 3.76], P = 0.424; endotracheal intubation vs. spontaneous breathing, OR = 0.82, 95% CI [0.39, 1.69], P = 0.592) showed a significant association with a prolonged postoperative LOS. Preoperative chronic obstructive pulmonary disease (OR = 2.78, 95% CI [1.05, 7.65], P = 0.040) and preoperative neutrophil count (OR = 1.13, 95% CI [1.01, 1.26], P = 0.029) were both significantly associated with the occurrence of postoperative pneumonia, while anesthesia type and airway management method were not. CONCLUSIONS Postoperative pneumonia was associated with prolonged postoperative LOS in very elderly patients undergoing hip fracture surgery, whereas anesthesia types and airway management methods show no association with prolonged postoperative LOS or postoperative pneumonia. Preoperative comorbidities, especially respiratory conditions and systemic inflammation, potentially play a substantial role in postoperative recovery.
Humans ; Hip Fractures/surgery* ; Aged, 80 and over ; Risk Factors ; Length of Stay ; Female ; Male ; Retrospective Studies ; Postoperative Complications/etiology*

This study was conducted retrospectively on a cohort of 68 patients with steroid 5 α-reductase 2 (SRD5A2) deficiency and 46,XY disorders of sex development (DSD). Whole-exon sequencing revealed 28 variants of SRD5A2 , and further analysis identified seven novel mutants. The preponderance of variants was observed in exon 1 and exon 4, specifically within the nicotinamide adenine dinucleotide phosphate (NADPH)-binding region. Among the entire cohort, 53 patients underwent initial surgery at Sichuan Provincial People's Hospital (Chengdu, China). The external genitalia scores (EGS) of these participants varied from 2.0 to 11.0, with a mean of 6.8 (standard deviation [s.d.]: 2.5). Thirty patients consented to hormone testing. Their average testosterone-to-dihydrotestosterone (T/DHT) ratio was 49.3 (s.d.: 23.4). Genetic testing identified four patients with EGS scores between 6 and 9 as having this syndrome; and their T/DHT ratios were below the diagnostic threshold. Furthermore, assessments conducted using the crystal structure of human SRD5A2 have provided insights into the potential pathogenic mechanisms of these novel variants. These mechanisms include interference with NADPH binding (c.356G>C, c.365A>G, c.492C>G, and c.662T>G) and destabilization of the protein structure (c.727C>T). The c.446-1G>T and c.380delG variants were verified to result in large alterations in the transcripts. Seven novel variations were identified, and the variant database for the SRD5A2 gene was expanded. These findings contribute to the progress of diagnostic and therapeutic approaches for individuals with SRD5A2 deficiency.
Humans ; 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/genetics* ; Disorder of Sex Development, 46,XY/blood* ; Male ; Membrane Proteins/genetics* ; Child, Preschool ; Child ; Retrospective Studies ; Adolescent ; Female ; Mutation ; Testosterone/blood* ; Infant ; Dihydrotestosterone/blood*

OBJECTIVE: CRISPR-Cas protects bacteria from exogenous DNA invasion and is associated with bacterial biofilm formation and pathogenicity. METHODS: We analyzed the type I-F CRISPR-Cas system of Legionella pneumophila WX48, including Cas1, Cas2-Cas3, Csy1, Csy2, Csy3, and Cas6f, along with downstream CRISPR arrays. We explored the effects of the CRISPR-Cas system on the in vitro growth, biofilm-forming ability, and pathogenicity of L. pneumophila through constructing gene deletion mutants. RESULTS: The type I-F CRISPR-Cas system did not affect the in vitro growth of wild-type or mutant strains. The biofilm formation and intracellular proliferation of the mutant strains were weaker than those of the wild type owing to the regulation of type IV pili and Dot/Icm type IV secretion systems. In particular, Cas6f deletion strongly inhibited these processes. CONCLUSION The type I-F CRISPR-Cas system may reduce biofilm formation and intracellular proliferation in L. pneumophila.
Legionella pneumophila/pathogenicity* ; CRISPR-Cas Systems ; Biofilms/growth & development* ; Phenotype ; Bacterial Proteins/metabolism* ; Gene Deletion

Intraperitoneal administration of timosaponin A-III (TA-III) has therapeutic effects on high-fat diet-induced metabolic dysfunction-associated steatotic liver disease (MASLD), but oral administration has no effect. This suggests that gut microbiota may affect the oral bioavailability of TA-III. Metabolic dysfunction-associated steatohepatitis (MASH) is an inflammatory subtype of MASLD. To investigate the therapeutic effect of different administration modes of TA-III on MASH and its relationship with gut microbiota metabolism. In this study, a MASH mouse model was induced by choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD). Comparing the therapeutic effect of intraperitoneal injection (10 mg·kg^-1, ip) and intragastric administration (100 mg·kg^-1, ig) of TA-III. The concentration of TA-III in serum of rats under the two administration modes was analyzed. On this basis, the metabolic effect of gut microbiota on TA-III in mice was verified by the experiment of metabolism of gut microbiota in vitro. The pharmacokinetic experiment of combined antibiotic intervention in mice further verified the metabolism of TA-III by gut microbiota in mice. Finally, the concentration of TA-III in serum of mice after the administration of TA-III by intragastric administration under different antibiotic intervention conditions was compared, and 16S rRNA sequencing analysis was combined to find the key bacteria that may participate in the metabolism of TA-III. The animal welfare and experimental procedures in this paper were in accordance with the provisions of the Animal Ethics Committee of Shanghai University of Traditional Chinese Medicine. The ethics approval number is PZSHUTCM2307030004 and PZSHUTCM2310200003. The results showed that TA-III (10 mg·kg^-1, ip) had definite therapeutic effect on MASH mice, but TA-III (100 mg·kg^-1, ig) was ineffective. The analysis showed that the prototype concentration of TA-III in serum and liver of mice in TA-III (100 mg·kg^-1, ig) was significantly lower than TA-III (10 mg·kg^-1, ip), suggesting that the oral administration of TA-III may be metabolized by gut microbiota. The concentration of TA-III in serum of streptomycin (Str) treated mice was higher than normal mice. Combined with 16S rRNA gene sequencing analysis, it was found that the abundance of Akkermansia_muciniphila (A. muciniphila) was significantly reduced in the Str group. In vitro experiments showed that A. muciniphila could metabolize TA-III. In conclusion, gut microbiota is an important factor affecting the efficacy of TA-III administration through the gastrointestinal tract, in which A. muciniphila may play an important role.

Objective Little is known about the association between whole-blood nicotinamide adenine dinucleotide(NAD+)levels and nabothian cysts.This study aimed to assess the association between NAD+levels and nabothian cysts in healthy Chinese women. Methods Multivariate logistic regression analysis was performed to analyze the association between NAD+levels and nabothian cysts. Results The mean age was 43.0±11.5 years,and the mean level of NAD+was 31.3±5.3 μmol/L.Nabothian cysts occurred in 184(27.7%)participants,with single and multiple cysts in 100(15.0%)and 84(12.6%)participants,respectively.The total nabothian cyst prevalence gradually decreased from 37.4%to 21.6%from Q1 to Q4 of NAD+and the prevalence of single and multiple nabothian cysts also decreased across the NAD+quartiles.As compared with the highest NAD+quartile(≥34.4 μmol/L),the adjusted odds ratios with 95%confidence interval of the NAD+Q1 was 1.89(1.14-3.14)for total nabothian cysts.The risk of total and single nabothian cysts linearly decreased with increasing NAD+levels,while the risk of multiple nabothian cysts decreased more rapidly at NAD+levels of 28.0 to 35.0 μmol/L. Conclusion:Low NAD+levels were associated with an increased risk of total and multiple nabothian cysts.

Objective To determine the acetylation level of nucleophosmin(NPM)in female breast cancer and to discuss its function through mutation of modified lysine sites.To construct positive and negative NPM mutants on its acetylated lysine sites and to express them in breast cancer cells.Methods Acetylation level and acetylated lysine sites of NPM in three breast cancer tissues and para-carcinoma tissues were detected by acetylome technology;NPM mutants were constructed by site-directed mutagenesis PCR,specific PCR products were digested by DpnI and transformed into Escherichia coli(E.coli)to obtain specific plasmids for mutants;The accuracy of mutants were verified by double restriction enzyme digestion and sequencing;The mutants were expressed in BT-549 cells by transient transfection and verified by RT-PCR method.Protein expression and acetylation level of NPM were validated by Western blotting;Function of NPM acetylation was analyzed by proteomic detection and bioinformatic analysis.Results The 27th and 32nd lysine of NPM were highly acetylated in breast cancer tissues,which were 2.76 and 2.22 times higher than those in adjacent normal tissues,respectively;The NPM mutants showed the same molecular weight as that of wild type NPM and contained expected mutation sites;Corresponding NPM mRNA levels of BT-549 cells transfected with NPM mutants were significantly increased.With the increase of wild type NPM expression level,NPM acetylation level increased,while decreased after 27th lysine underwent negative mutation.NPM acetylation can significantly change the expression levels of 101 proteins in BT-549 cells,which are enriched in regulation of cellular macromolecule biosynthesis,DNA-template transcription,RNA biosynthesis and RNA metabolism process.Conclusion NPM is highly acetylated in breast cancer and can play a key role in cellular macromolecule biosynthesis,DNA-templated transcription,RNA biosynthesis and RNA metabolism process.

Objective To investigate the effect of MALAT1 expressions on cell proliferation and apoptosis in astrocytes by regulating mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase(ERK1,2)pathway.Methods The MALAT1 gene was knocked down and over-expressed in C8-D1A cells by lentiviral and plasmid vectors,respectively.The expressions of MALAT1,cell proliferation-related markers(Ki67,MCM2,PCNA)and apoptosis-related proteins(Caspase-3,Bax,Bcl-2)were detected by quantitative real-time polymerase chain reaction(qPCR).CCK-8 assay and flow cytometry were used for cell proliferation and apoptosis in C8-D1A cells.Immunofluorescence was adopted to detect the protein expressions of Caspase-3 and Ki67.Western blotting was used to detect the protein expressions of Caspase-3,Bax,Bcl-2,ERK1/2,p-ERK1/2,p38MAPK and p-p38MAPK.Results Compared with the control group,over-expressed MALAT1 inhibited cell proliferation and induced cell apoptosis in C8-D1A cells while the knockdown of MALAT1 significantly enhanced cell proliferation and anti-apoptotic ability in C8-D1A cells.The proportion of C8-D1A cells in G0/G1-phase and G2/M-phase was higher than in the control group as evidenced by flow cytometry,but was lower in S-phase.Meanwhile,data showed that Caspase-3 was increased while p-ERK1/2 was decreased in terms of protein levels.The mRNA expressions of Ki67 and PCNA were decreased.After knockdown of MALAT1,the proportion of C8-D1A cells in S-phase was higher,but was lower in G2/M-phase.The protein expressions of Caspase-3 and Bax decreased while those of p-ERK1/2 and p-p38MAPK increased.The mRNA expressions of Ki67,MCM2 and PCNA were increased.The differences were all statistically significant(P＜0.05).Conclusion MALAT1 promotes astrocyte apoptosis and inhibits proliferation by regulating the MAPK/ERK1,2 signaling pathway.