Effect of HLA Genotype on Anti-PD-1 Antibody Treatment for Advanced Renal Cell Carcinoma in the SNiP-RCC Study.

Immune checkpoint blockade therapies are widely used for cancer treatment, including advanced renal cell carcinoma (RCC). This study aimed to investigate the impact of zygosity in HLA genes and individual HLA genotypes on the efficacy of an anti-PD-1 Ab, nivolumab, in treating advanced RCC. Patient enrollment was conducted across 23 institutions in Japan from August 19, 2019, to September 30, 2020, with follow-up concluding on March 31, 2021. HLA genotype imputation of HLA-A, B, and C, DQB1, and DRB1 loci was performed. Among 222 patients, the presence of at least one homozygosity of the HLA-II allele significantly improved the best objective response (hazard ratio, 0.34; 95% confidence interval, 0.21-0.96; p = 0.042). The HLA evolutionary divergence (HED) of the HLA-A and HLA-B loci was higher than the HLA-C (p < 0.0001 and p < 0.0001, respectively), with high HED of the HLA-B locus correlating to clinical benefits in nivolumab treatment (hazard ratio, 0.44; 95% confidence interval, 0.21-0.90; p = 0.024) and improving cancer-specific survival compared with the low group (p = 0.0202). Additionally, high HED of the HLA-B locus was correlated with the number of infiltrated CD8+ cells in the tumor microenvironment (correlation coefficient, 0.4042). These findings indicate that the diversity of the HLA-B locus plays a significant role in the anti-tumor effect of nivolumab treatment in advanced RCC, potentially offering insights for improved risk stratification in nivolumab treatment and leading to better medical management of advanced RCC.

Robot-assisted partial nephrectomy in younger versus older adults with renal cell carcinoma: a propensity score-matched analysis.

PURPOSE: Our study aimed to compare the surgical outcomes of robot-assisted partial nephrectomy (RAPN) between younger and older patients after adjusting for their background differences. We particularly assessed RAPN outcomes and safety in older patients. METHODS: We retrospectively evaluated 559 patients clinically diagnosed with T1 renal cell carcinoma (RCC) and treated with RAPN between 2013 and 2022 at five institutions in Japan. The patients were classified into two groups according to their age during surgery (younger group: < 75 years, older group: ≥ 75 years). Propensity score matching (PSM) was performed to adjust for the differences in the backgrounds between younger and older patients, and surgical outcomes were compared. RESULTS: Among the 559 patients, 422 (75.5%) and 137 (24.5%) were classified into the younger and older groups, respectively; 204 and 102 patients from the younger and older groups were matched according to PSM, respectively. Subsequently, patient characteristics other than age were not significantly different between the two groups. In the matched cohort, the older group had more patients with major complications (younger, 3.0%; older, 8.8%; P = 0.045). CONCLUSION: Surgical outcomes of RAPN in older patients with RCC were comparable with those in younger patients, although older patients experiencedsignificantly more complications than younger patients. These results suggest the need for further detailed preoperative evaluation and appropriate postoperative management in older patients receiving RAPN.

Expression of RNautophagy/DNautophagy-related genes is regulated under control of an innate immune receptor.

Double-stranded RNA (dsRNA) is a molecular pattern uniquely produced in cells infected with various viruses as a product or byproduct of replication. Cells detect such molecules, which indicate non-self invasion, and induce diverse immune responses to eliminate them. The degradation of virus-derived molecules can also play a role in the removal of pathogens and suppression of their replication. RNautophagy and DNautophagy are cellular degradative pathways in which RNA and DNA are directly imported into a hydrolytic organelle, the lysosome. Two lysosomal membrane proteins, SIDT2 and LAMP2C, mediate nucleic acid uptake via this pathway. Here, we showed that the expression of both SIDT2 and LAMP2C is selectively upregulated during the intracellular detection of poly(I:C), a synthetic analog of dsRNA that mimics viral infection. The upregulation of these two gene products upon poly(I:C) introduction was transient and synchronized. We also observed that the induction of SIDT2 and LAMP2C expression by poly(I:C) was dependent on MDA5, a cytoplasmic innate immune receptor that directly recognizes poly(I:C) and induces various antiviral responses. Finally, we showed that lysosomes can target viral RNA for degradation via RNautophagy and may suppress viral replication. Our results revealed a novel degradative pathway in cells as a downstream component of the innate immune response and provided evidence suggesting that the degradation of viral nucleic acids via RNautophagy/DNautophagy contributes to the suppression of viral replication.

Association of lung immune prognostic index with survival outcomes in patients with metastatic renal cell carcinoma treated with nivolumab plus ipilimumab.

OBJECTIVE: Lung immune prognostic index is based on derived neutrophil-to-lymphocyte ratio and lactate dehydrogenase level. Lung immune prognostic index has reported association with survival outcomes in patients with various malignancies undergoing treatment with immune checkpoint inhibitors. However, the prognostic impact of pre-treatment lung immune prognostic index in patients with metastatic renal cell carcinoma receiving nivolumab plus ipilimumab treatment remains unclear. This study examines the association between lung immune prognostic index and outcomes in this setting. METHODS: We retrospectively evaluated 156 patients with metastatic renal cell carcinoma treated with nivolumab plus ipilimumab at eight institutions. We assessed the associations between pre-treatment lung immune prognostic index and survival outcomes including progression-free survival, second progression-free survival (PFS2), cancer-specific survival and overall survival. RESULTS: Patients were classified into good (n = 84, 54%), intermediate (n = 52, 33%) and poor (n = 20, 13%) lung immune prognostic index groups. Progression-free survival did not significantly differ between lung immune prognostic index groups, but there was significant difference in PFS2, cancer-specific survival and overall survival. In multivariable Cox proportional hazard analyses, high pre-treatment lung immune prognostic index was a significant predictor of poor PFS2 (vs. good group, intermediate group: P = 0.01 and poor group: P = 0.04) and poor overall survival (vs. good group, intermediate group: P = 0.01 and poor group: P < 0.01). Moreover, the patients with poor lung immune prognostic index had significantly poorer cancer-specific survival than those with good LIPI (P < 0.01). CONCLUSIONS: High pre-treatment LIPI is suggested by our results to be a significant independent predictor of poor prognosis in patients receiving nivolumab plus ipilimumab for metastatic renal cell carcinoma.

Linear dichroism reveals the perpendicular orientation of DNA bases in the RecA and Rad51 recombinase filaments: A possible mechanism for the strand exchange reaction.

Linear dichroism spectroscopy is used to investigate the structure of RecA family recombinase filaments (RecA and Rad51 proteins) with DNA for clarifying the molecular mechanism of DNA strand exchange promoted by these proteins and its activation. The measurements show that the recombinases promote the perpendicular base orientation of single-stranded DNA only in the presence of activators, indicating the importance of base orientation in the reaction. We summarize the results and discuss the role of DNA base orientation.

The community of lactic acid bacteria during kimoto-style seed mash making process and its control.

Kimoto-style seed mash making processes such as the kimoto and yamahai-moto processes are driven by various microorganisms, and it is very important to make lactic acid bacteria grow stably for the brewing of a sake product with consistent quality. A model of bacterial transition from spherical lactic acid bacteria to rod-shaped lactic acid bacteria during kimoto-making has been advocated, but the model cannot explain all cases of a transition of a bacterial community during kimoto-making at various breweries. Several studies have described unique bacterial transition patterns that differ from those considered in the proposed model, and it is possible that factors such as differences in the initial bacterial community among breweries may cause the diversity of bacterial transitions. In this minireview, I summarize the research concerning the community of lactic acid bacteria during the kimoto-style seed mash making process, and I discuss how stable lactic acid fermentation can be achieved.

A conserved Ctp1/CtIP C-terminal peptide stimulates Mre11 endonuclease activity.

The Mre11-Rad50-Nbs1 complex (MRN) is important for repairing DNA double-strand breaks (DSBs) by homologous recombination (HR). The endonuclease activity of MRN is critical for resecting 5'-ended DNA strands at DSB ends, producing 3'-ended single-strand DNA, a prerequisite for HR. This endonuclease activity is stimulated by Ctp1, the Schizosaccharomyces pombe homolog of human CtIP. Here, with purified proteins, we show that Ctp1 phosphorylation stimulates MRN endonuclease activity by inducing the association of Ctp1 with Nbs1. The highly conserved extreme C terminus of Ctp1 is indispensable for MRN activation. Importantly, a polypeptide composed of the conserved 15 amino acids at the C terminus of Ctp1 (CT15) is sufficient to stimulate Mre11 endonuclease activity. Furthermore, the CT15 equivalent from CtIP can stimulate human MRE11 endonuclease activity, arguing for the generality of this stimulatory mechanism. Thus, we propose that Nbs1-mediated recruitment of CT15 plays a pivotal role in the activation of the Mre11 endonuclease by Ctp1/CtIP.

Annual record on the number of general urological surgeries registered in the National Clinical Database system between April 2018 and December 2021 in Japan.

BACKGROUND: The Japanese National Clinical Database (NCD) is a large-scale, nationwide, web-based data entry system that covers the majority of surgical cases performed in Japan. An NCD specializing in urological surgery was launched based on the NCD system in 2018. METHODS: All urological surgeries performed at more than 1000 institutions were registered from 2018. We herein report the number of surgeries conducted as stipulated in the "Certified Urology Surgeon Training Curriculum" between April 2018 and December 2021. RESULTS: A total of 1 377 677 cases were registered from 1185 facilities nationwide under the initiative of the Japanese Urological Association. We examined the number of procedures performed every year for each of the 10 categories. CONCLUSIONS: The NCD system sustainably provides important information relating to the preoperative status, operational outcome, and best practice for urological surgery in Japan.

Retroperitoneal cutaneous ureterostomy following radical cystectomy: A multicenter comparative study of robotic versus open surgery.

INTRODUCTION: The aim of this study was to evaluate the differences in perioperative outcomes of cutaneous ureterostomy (CUS) between open surgery (open radical cystectomy, ORC) and robot-assisted surgery (robot-assisted radical cystectomy, RARC), including the stent-free rate, readmission rates due to urinary tract infection (UTI), and changes in renal function. METHODS: Between 2005 and 2023, a total of 37 patients underwent CUS following ORC, while 24 patients underwent CUS following RARC. Perioperative outcomes were compared between these two groups. RESULTS: The patients in the RARC group were significantly older (p = 0.007) and had a significantly higher proportion of high-risk cases with ASA-PS ≥3 (p = 0.002). In addition, RARC was associated with a significantly lower estimated blood loss (p < 0.001) and a reduced transfusion rate (p = 0.003). Postoperative complication rates and the stent-free rate were comparable between the ORC and RARC groups. Throughout a median follow-up period of 2.6 years, rates of readmission due to UTI did not differ significantly between the two groups. Moreover, there were no differences in the change in estimated glomerular filtration rate before and after surgery and the 3-year survival rates were similar across both groups. CONCLUSIONS: CUS following RARC appears to offer a safer alternative compared with CUS following ORC, and the stent-free rates are comparable. The significantly lower estimated blood loss and transfusion rate associated with RARC are particularly favorable for elderly patients, those who are frail, and individuals with multiple comorbidities.

Human Rad51 Protein Requires Higher Concentrations of Calcium Ions for D-Loop Formation than for Oligonucleotide Strand Exchange.

Human Rad51 protein (HsRad51)-promoted DNA strand exchange, a crucial step in homologous recombination, is regulated by proteins and calcium ions. Both the activator protein Swi5/Sfr1 and Ca2+ ions stimulate different reaction steps and induce perpendicular DNA base alignment in the presynaptic complex. To investigate the role of base orientation in the strand exchange reaction, we examined the Ca2+ concentration dependence of strand exchange activities and structural changes in the presynaptic complex. Our results show that optimal D-loop formation (strand exchange with closed circular DNA) required Ca2+ concentrations greater than 5 mM, whereas 1 mM Ca2+ was sufficient for strand exchange between two oligonucleotides. Structural changes indicated by increased fluorescence intensity of poly(dεA) (a poly(dA) analog) reached a plateau at 1 mM Ca2+. Ca2+ > 2 mM was required for saturation of linear dichroism signal intensity at 260 nm, associated with rigid perpendicular DNA base orientation, suggesting a correlation with the stimulation of D-loop formation. Therefore, Ca2+ exerts two different effects. Thermal stability measurements suggest that HsRad51 binds two Ca2+ ions with KD values of 0.2 and 2.5 mM, implying that one step is stimulated by one Ca2+ bond and the other by two Ca2+ bonds. Our results indicate parallels between the Mg2+ activation of RecA and the Ca2+ activation of HsRad51.

Insulin receptor expression to predict resistance to axitinib and elucidation of the underlying molecular mechanism in metastatic renal cell carcinoma.

BACKGROUND: The study aimed to examine the significance of insulin receptor (INSR) expression in predicting resistance to axitinib in clear cell renal cell carcinoma (ccRCC). METHODS: Clinicopathological data were collected from 36 consecutive patients with metastatic RCC who received axitinib. Thirty-three primary tumours were obtained for immunohistochemistry. Patient-derived xenograft (PDX) models were created by transplanting primary tumours into immunodeficient mice, establishing axitinib-resistant PDX models. RCC cell lines were co-cultured with human renal glomerular endothelial cells (HGECs) treated with siRNA of INSR (HGEC-siINSR). Gene expression alteration was analysed using microarray. RESULTS: The patients with low INSR expression who received axitinib had a poorer outcome. Multivariate analysis showed that INSR expression was the independent predictor of progression-free survival. INSR expression decreased in axitinib-resistant PDX tumours. RCC cell lines showed upregulated interferon responses and highly increased interferon-ß levels by co-culturing with HGEC-siINSR. HGECs showed decreased INSR and increased interferon-ß after axitinib administration. RCC cell lines co-cultured with HGEC-siINSR showed high programmed death-ligand 1 (PD-L1) expression, which increased after interferon-ß administration. CONCLUSIONS: Decreased INSR in RCC could be a biomarker to predict axitinib resistance. Regarding the resistant mechanism, vascular endothelial cells with decreased INSR in RCC may secrete interferon-ß and induce PD-L1.

Cytoskeletal fractionation identifies LMO7 as a positive regulator of fibroblast polarization and directed migration.

Cell migration is a cytoskeleton-driven cellular process involved in physiological and pathological events such as embryonic development and cancer metastasis. Fibroblasts have often been used to elucidate the mechanism of cell migration due to their high morphological polarity and migratory activity. We recently reported that human lung fibroblasts migrate straight for a long duration without external stimuli, which phenomenon we named intrinsic and directed migration (IDM) of fibroblasts. In this study, we explored proteins involved in IDM in order to elucidate the molecular mechanism. First, we focused on the differences in morphology and migratory behaviors between normal and immortalized fibroblasts-the former exhibit obvious polarity and IDM; the latter exhibit poorly polarized morphology and random migration. We compared the abundance of proteins functioning as the cytoskeletal components between them through proteomic analysis and found that LIM domain only protein 7 (LMO7) is overwhelmingly incorporated into the cytoskeletons of normal fibroblasts. Depletion of LMO7 inhibited the directed migration of normal fibroblast on the fibronectin (FN)-rich surface, suggesting that LMO7 is important for IDM. Moreover, on the FN-free surface, LMO7-depleted fibroblasts often failed to establish morphological polarity and hardly migrated. Thus, the present study identified LMO7 as a positive regulator of fibroblast polarization and IDM, especially in an environment where integrin-mediated substrate attachment is insufficient.

Effect of genetic polymorphisms on outcomes following nivolumab for advanced renal cell carcinoma in the SNiP-RCC trial.

BACKGROUND: Anti-PD-1 antibodies are widely used for cancer treatment including advanced renal cell carcinoma (RCC). However, their therapeutic and adverse effects vary among patients. This study aimed to identify genetic markers that predict outcome after nivolumab anti-PD-1 antibody treatment for advanced RCC. METHODS: This study was registered on the website of the University Hospital Medical Information Network (protocol ID, UMIN000037739). Patient enrollment was conducted at 23 institutions in Japan between August 19, 2019, and September 30, 2020. Patient follow-up ended on March 31, 2021. Patients were treated with nivolumab for advanced clear cell RCC. A genome-wide association study was performed in the development set, while genotyping of target regions in the validation set was undertaken. Single nucleotide polymorphisms (SNPs) in genes of interest CD274, PDCD1LG2 and PDCD1 were genotyped in the combined set. The primary endpoint was the association of SNPs with objective response following nivolumab treatment. As secondary endpoints, the associations of SNPs with radiographic progression-free survival (rPFS) and treatment-related grade ≥ 3 adverse events (AEs) were evaluated. RESULTS: A genome-wide association study followed by a validation study identified that SNPs in FARP1 (rs643896 and rs685736) were associated with objective response and rPFS but not AEs following nivolumab treatment. Furthermore, SNPs in PDCD1LG2 (rs822339 and rs1411262) were associated with objective response, rPFS, and AEs following nivolumab treatment. Genetic risk category determined according to the number of risk alleles in SNPs (rs643896 in FARP1 and rs4527932 in PDCD1LG2) excellently predicted objective response and rPFS in nivolumab treatment. CONCLUSION: This study revealed that SNPs in FARP1 and PDCD1LG2 were correlated with outcome in nivolumab treatment. The use of these SNPs may be beneficial in selecting appropriate treatment for individual patients and may contribute to personalized medicine.

Analyses of BER-referred noise-to-signal ratio in online measurements of high-baud-rate coherent receivers.

Digital coherent transmission features a very large transmission bandwidth and has played a main role in core optical transmission networks. With the progress of semiconductor technologies, practical coherent transceivers with rates over 100 Gbaud are becoming feasible. With such advances, the transceiver components must have lower power consumption and lower costs, and it becomes important to know how each component contributes to the overall transmission performance. Here, to decompose the effects of noise factors in high-baud-rate DP-16QAM transmissions, we used the theoretical relationship between the bit error rate (BER) and noise-to-signal ratio (NSR) and performed linear analyses. The NSR could be decomposed into individual noise contributions according to dependences on the inverse signal and local photocurrents. The obtained parameters were shown to be useful for predicting required optical signal-to-noise ratio (ROSNR) characteristics.

Evaluation of the Effects of Power-Frequency Magnetic Field Exposure on B-Cell Differentiation From Human Hematopoietic Stem/Progenitor Cells.

The causal relationship between exposure to power-frequency magnetic fields (MFs) and childhood leukemia has long been controversial. The most common type of childhood leukemia is acute B-lymphoblastic leukemia caused by abnormal proliferation of B cells in the early differentiation process. Here, we focused on B-cell early differentiation and aimed to evaluate the effects of exposing cells to power-frequency MF. First, we optimized an in vitro differentiation protocol of human hematopoietic stem/progenitor cells (HSPCs) to B-cell lineages. Following validation of the responsiveness of the protocol to additional stimulations and the uniformity of the experimental conditions, human HSPCs were continuously exposed to 300 mT of 50 Hz MF for 35 days of the differentiation process. These experiments were performed in a blinded manner. The percentages of myeloid or lymphoid cells and their degree of differentiation from pro-B to immature-B cells in the MF-exposed group showed no significant changes compared with those in the control group. Furthermore, the expression levels of recombination-activating gene (RAG)1 and RAG2 in the B cells were also similar to those in the control group. These results indicate that exposure to 50 Hz MF at 300 mT does not affect the human B-cell early differentiation from HSPCs. © 2023 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.

Two auxiliary factors promote Dmc1-driven DNA strand exchange via stepwise mechanisms.

Homologous recombination (HR) is a universal mechanism operating in somatic and germ-line cells, where it contributes to the maintenance of genome stability and ensures the faithful distribution of genetic material, respectively. The ability to identify and exchange the strands of two homologous DNA molecules lies at the heart of HR and is mediated by RecA-family recombinases. Dmc1 is a meiosis-specific RecA homolog in eukaryotes, playing a predominant role in meiotic HR. However, Dmc1 cannot function without its two major auxiliary factor complexes, Swi5-Sfr1 and Hop2-Mnd1. Through biochemical reconstitutions, we demonstrate that Swi5-Sfr1 and Hop2-Mnd1 make unique contributions to stimulate Dmc1-driven strand exchange in a synergistic manner. Mechanistically, Swi5-Sfr1 promotes establishment of the Dmc1 nucleoprotein filament, whereas Hop2-Mnd1 defines a critical, rate-limiting step in initiating strand exchange. Following execution of this function, we propose that Swi5-Sfr1 then promotes strand exchange with Hop2-Mnd1. Thus, our findings elucidate distinct yet complementary roles of two auxiliary factors in Dmc1-driven strand exchange, providing mechanistic insights into some of the most critical steps in meiotic HR.

Comparison of robot-assisted partial nephrectomy with soft coagulation and double-layer technique for complex and non-complex tumors.

OBJECTIVES: To compare the postoperative outcomes of robot-assisted partial nephrectomy when only the inner layer is sutured (single-layer technique with soft coagulation) with those when sutures are placed in the inner and outer layers (double-layer technique) in patients with and without complex renal tumors. METHODS: This retrospective three-institution study included 371 patients with renal tumors who underwent robot-assisted partial nephrectomy with a double-layer technique or a single-layer technique with soft coagulation. Tumors that were cT1b, completely embedded, located in the renal portal, or had a RENAL score of ≥10 were considered complex. Relevant data were collected from hospital records. Propensity score matching was performed to minimize selection bias. RESULTS: Propensity score matching created 83 patient pairs with non-complex tumors and 32 with complex tumors. Regardless of tumor complexity, there was no significant difference in operation time, console time, warm ischemia time, positive surgical margin rate, or length of hospital stay between the double-layer and single-layer groups. Although Clavien-Dindo grade I-II urinomas not requiring intervention were significantly more common in the single-layer group regardless of tumor complexity, there was no significant between-group difference in the rate of decline in renal function or grade III-IV complications. CONCLUSION: Single-layer suturing with soft coagulation achieves renal function and perioperative outcomes comparable to those of double-layer suturing regardless of complexity.

Clinical factors for tumor response, progression, and survival in nivolumab for advanced renal cell carcinoma in the SNiP-RCC study.

BACKGROUND: This study is part of the SNPs in Nivolumab PD-1 inhibitor for RCC (SNiP-RCC). Here we aimed to reveal clinical factors for tumor response, progression, and survival in nivolumab for advanced clear cell renal cell carcinoma (RCC) in Japanese patients. METHODS: We included patients from 23 institutions in Japan. We evaluated the objective response, radiographic progression-free survival (PFS), overall survival (OS), and treatment-related grade ≥ 3 (serious adverse events [SAEs]). RESULTS: We included 222 patients. The median age was 69 years (interquartile range 62-74 years), and 71% of the patients were male. Pancreas metastasis, lung metastases, prior cytokine therapy, and SAEs, were associated with objective response. The median PFS was 18 months. Liver metastases (hazard ratio [HR], 1.61), age ≥ 75 (HR, 0.48), previous resection of primary sites (HR, 0.47), and SAEs (HR, 0.47) were independent prognostic factors for PFS. Karnofsky Performance Status <70 (HR, 2.90), high platelets (HR, 4.48), previous resection of primary sites (HR, 0.23), and pathological grade (HR, 0.19 for grade 2 and HR, 0.12 for grade 3) were independent prognostic factors for OS. SAEs were reported in 45 (20.3%) cases. In the group of patients with prior nephrectomy, SAEs were associated with objective response, PFS, and OS. CONCLUSION: The SNiP-RCC study identified clinical parameters correlated with treatment outcomes in Japanese patients with priorly treated advanced clear cell RCC undergoing nivolumab monotherapy.

Linear Dichroism Measurements for the Study of Protein-DNA Interactions.

Linear dichroism (LD) is a differential polarized light absorption spectroscopy used for studying filamentous molecules such as DNA and protein filaments. In this study, we review the applications of LD for the analysis of DNA-protein interactions. LD signals can be measured in a solution by aligning the sample using flow-induced shear force or a strong electric field. The signal generated is related to the local orientation of chromophores, such as DNA bases, relative to the filament axis. LD can thus assess the tilt and roll of DNA bases and distinguish intercalating from groove-binding ligands. The intensity of the LD signal depends upon the degree of macroscopic orientation. Therefore, DNA shortening and bending can be detected by a decrease in LD signal intensity. As examples of LD applications, we present a kinetic study of DNA digestion by restriction enzymes and structural analyses of homologous recombination intermediates, i.e., RecA and Rad51 recombinase complexes with single-stranded DNA. LD shows that the DNA bases in these complexes are preferentially oriented perpendicular to the filament axis only in the presence of activators, suggesting the importance of organized base orientation for the reaction. LD measurements detect DNA bending by the CRP transcription activator protein, as well as by the UvrB DNA repair protein. LD can thus provide information about the structures of protein-DNA complexes under various conditions and in real time.

Genes for tRNA recycling are upregulated in response to infection with Theiler's mouse encephalitis virus.

The concept of tRNA recycling has recently emerged from the studies of ribosome-associated quality control. Therein tRNase ZS removes the 2', 3'>p from the ANKZF1-cleaved tRNA and the subsequent TRNT1 action re-generates the intact tRNA. To know the roles of the tRNA recycling in vivo, we investigated how viral infection affects the tRNA recycling system by analyzing the mRNA levels of tRNase ZS and TRNT1. We found that both genes in HeLa cells are upregulated in response to infection of Theiler's mouse encephalitis virus but not to that of an influenza A virus. Upregulation was also observed in cells infected with encephalomyocarditis virus with reduced efficiency. The levels of the IFN-ß mRNA appeared to positively correlate with those of the tRNase ZS and TRNT1 mRNAs. The tRNase ZS gene may be regulated post-transcriptionally in the cells infected with Theiler's mouse encephalitis virus.