Vaccinia virus induces EMT-like transformation and RhoA-mediated mesenchymal migration.

The emerging outbreak of monkeypox is closely associated with the viral infection and spreading, threatening global public health. Virus-induced cell migration facilitates viral transmission. However, the mechanism underlying this type of cell migration remains unclear. Here we investigate the motility of cells infected by vaccinia virus (VACV), a close relative of monkeypox, through combining multi-omics analyses and high-resolution live-cell imaging. We find that, upon VACV infection, the epithelial cells undergo epithelial-mesenchymal transition-like transformation, during which they lose intercellular junctions and acquire the migratory capacity to promote viral spreading. After transformation, VACV-hijacked RhoA signaling significantly alters cellular morphology and rearranges the actin cytoskeleton involving the depolymerization of robust actin stress fibers, leading-edge protrusion formation, and the rear-edge recontraction, which coordinates VACV-induced cell migration. Our study reveals how poxviruses alter the epithelial phenotype and regulate RhoA signaling to induce fast migration, providing a unique perspective to understand the pathogenesis of poxviruses.

A Palladium-Catalyzed Borylation/Silica Gel Promoted Hydrolysis Sequence for the Synthesis of Hydroquinine-6'-Boric Acid and Its Applications.

Hydroquinine-6'-boric acid was first synthesized via a palladium-catalyzed borylation/silica gel promoted hydrolysis sequence of hydroquinine-derived triflate and bis(pinacolato)diboron. The newly designed chiral building block was subjected to the Suzuki-Miyaura cross-coupling reaction, Petasis reaction, and selenylation reaction, respectively, and all these reactions worked well to afford the corresponding 6'-functionalized hydroquinines with satisfactory results, demonstrating its extraordinary application potency.

Enhanced BCAT1 activity and BCAA metabolism promotes RhoC activity in cancer progression.

Increased expression of branched-chain amino acid transaminase 1 or 2 (BCAT1 and BCAT2) has been associated with aggressive phenotypes of different cancers. Here we identify a gain of function of BCAT1 glutamic acid to alanine mutation at codon 61 (BCAT1E61A) enriched around 2.8% in clinical gastric cancer samples. We found that BCAT1E61A confers higher enzymatic activity to boost branched-chain amino acid (BCAA) catabolism, accelerate cell growth and motility and contribute to tumor development. BCAT1 directly interacts with RhoC, leading to elevation of RhoC activity. Notably, the BCAA-derived metabolite, branched-chain α-keto acid directly binds to the small GTPase protein RhoC and promotes its activity. BCAT1 knockout-suppressed cell motility could be rescued by expressing BCAT1E61A or adding branched-chain α-keto acid. We also identified that candesartan acts as an inhibitor of BCAT1E61A, thus repressing RhoC activity and cancer cell motility in vitro and preventing peritoneal metastasis in vivo. Our study reveals a link between BCAA metabolism and cell motility and proliferation through regulating RhoC activation, with potential therapeutic implications for cancers.

ZnT8 loss-of-function accelerates functional maturation of hESC-derived ß cells and resists metabolic stress in diabetes.

Human embryonic stem cell-derived ß cells (SC-ß cells) hold great promise for treatment of diabetes, yet how to achieve functional maturation and protect them against metabolic stresses such as glucotoxicity and lipotoxicity remains elusive. Our single-cell RNA-seq analysis reveals that ZnT8 loss of function (LOF) accelerates the functional maturation of SC-ß cells. As a result, ZnT8 LOF improves glucose-stimulated insulin secretion (GSIS) by releasing the negative feedback of zinc inhibition on insulin secretion. Furthermore, we demonstrate that ZnT8 LOF mutations endow SC-ß cells with resistance to lipotoxicity/glucotoxicity-triggered cell death by alleviating endoplasmic reticulum (ER) stress through modulation of zinc levels. Importantly, transplantation of SC-ß cells with ZnT8 LOF into mice with preexisting diabetes significantly improves glycemia restoration and glucose tolerance. These findings highlight the beneficial effect of ZnT8 LOF on the functional maturation and survival of SC-ß cells that are useful as a potential source for cell replacement therapies.

Diet high in branched-chain amino acid promotes PDAC development by USP1-mediated BCAT2 stabilization.

BCAT2-mediated branched-chain amino acid (BCAA) catabolism is critical for pancreatic ductal adenocarcinoma (PDAC) development, especially at an early stage. However, whether a high-BCAA diet promotes PDAC development in vivo, and the underlying mechanism of BCAT2 upregulation, remain undefined. Here, we find that a high-BCAA diet promotes pancreatic intraepithelial neoplasia (PanIN) progression in LSL-KrasG12D/+ ; Pdx1-Cre (KC) mice. Moreover, we screened with an available deubiquitylase library which contains 31 members of USP family and identified that USP1 deubiquitylates BCAT2 at the K229 site. Furthermore, BCAA increases USP1 protein at the translational level via the GCN2-eIF2α pathway both in vitro and in vivo. More importantly, USP1 inhibition recedes cell proliferation and clone formation in PDAC cells and attenuates pancreas tumor growth in an orthotopic transplanted mice model. Consistently, a positive correlation between USP1 and BCAT2 is found in KC; LSL-KrasG12D/+ ; p53flox/+ ; Pdx1-Cre mice and clinical samples. Thus, a therapeutic targeting USP1-BCAT2-BCAA metabolic axis could be considered as a rational strategy for treatment of PDAC and precisive dietary intervention of BCAA has potentially translational significance.

Dietary folate drives methionine metabolism to promote cancer development by stabilizing MAT IIA.

Folic acid, served as dietary supplement, is closely linked to one-carbon metabolism and methionine metabolism. Previous clinical evidence indicated that folic acid supplementation displays dual effect on cancer development, promoting or suppressing tumor formation and progression. However, the underlying mechanism remains to be uncovered. Here, we report that high-folate diet significantly promotes cancer development in mice with hepatocellular carcinoma (HCC) induced by DEN/high-fat diet (HFD), simultaneously with increased expression of methionine adenosyltransferase 2A (gene name, MAT2A; protein name, MATIIα), the key enzyme in methionine metabolism, and acceleration of methionine cycle in cancer tissues. In contrast, folate-free diet reduces MATIIα expression and impedes HFD-induced HCC development. Notably, methionine metabolism is dynamically reprogrammed with valosin-containing protein p97/p47 complex-interacting protein (VCIP135) which functions as a deubiquitylating enzyme to bind and stabilize MATIIα in response to folic acid signal. Consistently, upregulation of MATIIα expression is positively correlated with increased VCIP135 protein level in human HCC tissues compared to adjacent tissues. Furthermore, liver-specific knockout of Mat2a remarkably abolishes the advocating effect of folic acid on HFD-induced HCC, demonstrating that the effect of high or free folate-diet on HFD-induced HCC relies on Mat2a. Moreover, folate and multiple intermediate metabolites in one-carbon metabolism are significantly decreased in vivo and in vitro upon Mat2a deletion. Together, folate promotes the integration of methionine and one-carbon metabolism, contributing to HCC development via hijacking MATIIα metabolic pathway. This study provides insight into folate-promoted cancer development, strongly recommending the tailor-made folate supplement guideline for both sub-healthy populations and patients with cancer expressing high level of MATIIα expression.

BCAA-BCKA axis regulates WAT browning through acetylation of PRDM16.

The link between branched-chain amino acids (BCAAs) and obesity has been known for decades but the functional role of BCAA metabolism in white adipose tissue (WAT) of obese individuals remains vague. Here, we show that mice with adipose tissue knockout of Bcat2, which converts BCAAs to branched-chain keto acids (BCKAs), are resistant to high-fat diet-induced obesity due to increased inguinal WAT browning and thermogenesis. Mechanistically, acetyl-CoA derived from BCKA suppresses WAT browning by acetylation of PR domain-containing protein 16 (PRDM16) at K915, disrupting the interaction between PRDM16 and peroxisome proliferator-activated receptor-γ (PPARγ) to maintain WAT characteristics. Depletion of BCKA-derived acetyl-CoA robustly prompts WAT browning and energy expenditure. In contrast, BCKA supplementation re-establishes high-fat diet-induced obesity in Bcat2 knockout mice. Moreover, telmisartan, an anti-hypertension drug, significantly represses Bcat2 activity via direct binding, resulting in enhanced WAT browning and reduced adiposity. Strikingly, BCKA supplementation reverses the lean phenotype conferred by telmisartan. Thus, we uncover the critical role of the BCAA-BCKA axis in WAT browning.

[Extraperitoneal robot-assisted laparoscopic radical prostatectomy through single incision: Establishment and application of a modified channel].

Objective: To assess the feasibility and validity of the establishment of a modified channel for extraperitoneal robot-assisted laparoscopic radical prostatectomy (RARP) through single incision. METHODS: From November 2020 to January 2021, 35 cases of localized PCa were treated by extraperitoneal RARP through single incision in our center. All the operations were performed by the same surgeon, none via the multichannel port for the establishment of the channel. We recorded and analyzed the intra- and postoperative parameters, operation cost, complications, pathological findings and follow-up data. RESULTS: All the operations were successfully completed, without conversion to open surgery or additional channels, or serious postoperative complications, the time for establishing the extraperitoneal space averaging 25.4 (20.0－45.0) min, the operation time 67.3 (35.0－125.0) min, intraoperative blood loss 75.5 (60.0－150.0) ml, time to first postoperative anal exhaust 26 (8－48) h, and postoperative hospital stay 7.89 (7－10) d. Postoperative pathology showed adenocarcinoma in all the cases, with Gleason score (GS) 3+3 in 9 (25.7%), GS 3+4 in 9 (25.7%), GS 4+3 in 8 (22.9%), and GS ≥ 8 in 9 (25.7%) of the cases, 23 (65.7%) in the

[Protective effects of total saponins of Codonopsis on ulcerative colitis induced by TNBS in rats and its mechanism].

Objective: To study the protective effects and mechanisms of total saponins of Codonopsis (TSC) on ulcerative colitis in rats. Methods: Fifty male Wistar rats were randomly divided into 5 groups: control group, model group, salazosulfadiazine (SASP) positive control group (0.3 g/kg), TSC high- and low-dose experimental groups(1.2, 0.4 g/kg). UC rat model was established by trinitrobenzene sulfonic acid (TNBS)/ ethanol enema. After administration for 21 days, the rats' symptoms and signs, disease activity index (DAI), colonic mucosal injury index (CMDI) and colonic tissue morphology were observed. The contents of superoxide dismutase (SOD), malondialdehyde (MDA), inflammatory cytokines interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor (TNF-α) in colon tissues were determined. Protein expression of nuclear nuclear transcription factor-κB (NF-κB) in colon tissues was detected. Finally, the effect of TCS therapy was evaluated. Results: Compared with the control group, the DAI and CMDI scores of the rats in the model group were increased significantly, meanwhile the colonic mucosa was seriously damaged, indicating that the model was successful. Compared with the model group, the TSC high and low dose groups could significantly reduce the DAI and CMDI score (P＜0.05) and improve the colonic mucosa form. TSC also could increase the SOD activity and decrease MDA content in colon tissues(P＜0.05), while inhibit the levels of IL-6 and TNF-α mRNA in the colon tissues and promote the expression of IL-10 mRNA (P＜0.01). At the same time, TSC reduced the expressions of NF-κB protein in the colon (P＜0.01). The TSC high-dose group was superior to the low-dose group (P＜0.05). Conclusion: TSC has significant protective effects on ulcerative colonic mucosal damage in UC rats, and there is a dose-dependent relationship; its mechanism may be related to anti-lipid peroxidation and inhibiting the NF-κB signaling pathway to regulate the release of inflammatory factors.

DaVinci robotic-assisted laparoscopic resection of parapelvic cavernous hemangioma: a case report.

BACKGROUND: Cavernous hemangioma, as a rare tumor, is difficult to differentiate from retroperitoneal lymphoma and paraganglioma. They are more difficult to excise completely through open surgery and traditional laparoscopic surgery. The study aimed to evaluate the role of DaVinci surgical system in laparoscopic resection of parapelvic cavernous hemangioma. CASE PRESENTATION: A 46-year-old female, who diagnosed as parapelvic cavernous hemangioma accompanying with thrombosis and calcification, was performed laparoscopic resection using DaVinci surgical system under general anesthesia. The patient well recovered without recurrence or spread of the lesion after operation for 3 months as well as hydronephrosis was significantly relieved. CONCLUSION: Laparoscopic resection of parapelvic cavernous hemangioma under the help of DaVinci surgical system was feasible and safe.

BCAT2-mediated BCAA catabolism is critical for development of pancreatic ductal adenocarcinoma.

Branched-chain amino acid (BCAA) metabolism is potentially linked with development of pancreatic ductal adenocarcinoma (PDAC)1-4. BCAA transaminase 2 (BCAT2) was essential for the collateral lethality conferred by deletion of malic enzymes in PDAC and the BCAA-BCAT metabolic pathway contributed to non-small-cell lung carcinomas (NSCLCs) other than PDAC3,4. However, the underlying mechanism remains undefined. Here we reveal that BCAT2 is elevated in mouse models and in human PDAC. Furthermore, pancreatic tissue-specific knockout of Bcat2 impedes progression of pancreatic intraepithelial neoplasia (PanIN) in LSL-KrasG12D/+; Pdx1-Cre (KC) mice. Functionally, BCAT2 enhances BCAA uptake to sustain BCAA catabolism and mitochondrial respiration. Notably, BCAA enhances growth of pancreatic ductal organoids from KC mice in a dose-dependent manner, whereas addition of branched-chain α-keto acid (BCKA) and nucleobases rescues growth of KC organoids that is suppressed by BCAT2 inhibitor. Moreover, KRAS stabilizes BCAT2, which is mediated by spleen tyrosine kinase (SYK) and E3 ligase tripartite-motif-containing protein 21 (TRIM21). In addition, BCAT2 inhibitor ameliorates PanIN formation in KC mice. Of note, a lower-BCAA diet also impedes PDAC development in mouse models of PDAC. Thus, BCAT2-mediated BCAA catabolism is critical for development of PDAC harbouring KRAS mutations. Targeting BCAT2 or lowering dietary BCAA may have translational significance.

Streptomyces salilacus sp. nov., an actinomycete isolated from a salt lake.

The taxonomic position of a novel actinomycete, strain TRM 41337T, isolated from sediment of a salt lake, Xiaoerkule Lake, Xinjiang, China, was determined by a polyphasic approach. Strain TRM 41337T grew optimally at 28 °C and in the presence of 1 % (w/v) NaCl. It grew at up to pH 12. The whole-cell sugars of strain TRM 41337T were ribose and xylose. The diagnostic diamino acid contained ll-diaminopimelic acid. The polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositolmannoside and two other unidentified phospholipids. The predominant menaquinones were MK-9(H8), MK-9, MK-9(H4) and MK-9(H6). The major fatty acids were iso-C16 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 1 H. Based on morphological and chemotaxonomic characteristics, the isolate was determined to belong to the genus Streptomyces. The phylogenetic tree based on its nearly complete 16S rRNA gene sequence (1498 nt) with representative strains showed that the strain consistently falls into a distinct phyletic lineage together with Streptomyces barkulensis DSM 42082T (97.48 % similarity) and a subclade consisting of Streptomyces fenghuangensis GIMN 4.003T (97.20 %), Streptomyces macrosporus NBRC 14748T (97.14 %) and Streptomyces radiopugnans R97T (97.01 %). On the basis of these data, strain TRM 41337T should be designated as a representative of a novel species of the genus Streptomyces, for which the name Streptomyces salilacus sp. nov. is proposed. The type strain is TRM 41337T (=CCTCC AA 2015030T=KCTC 39726T).

Rosiglitazone affects lumen formation in MDCKII cell through regulating apico-basal polarity.

This study aimed to investigate the potential mechanisms underlying the effects of Rosiglitazone on the apico-basal polarity in renal epithelial cells. 3D-MDCK model was used to study the lumen formation and localization of polarity proteins at the early stage of the establishment of the apico-basal polarity. The calcium switch model, immunofluorescence staining and measurement of transmembrane electrical impedance are employed to investigate the epithelial apico-basal polarity including the development and maintenance of apical domains and the formation of tight junction. MDCKII cells were cultured with 20 uM rosiglitazone or DMSO. Results showed Rosiglitazone reduced the percentage of single central lumen cysts, but the percentage of multiple lumen cysts increased. At the early stage of MDCKII cysts (2-5 cells), Rosiglitazone induced mislocalization of apical and basolateral membrane proteins. In the repolarization process of MDCKII cell induced by a calcium switch (CS), Rosiglitazone delayed the apical membrane domain development in the early phase of cell polarization; while during the maintenance phase of cell polarity, the apical domain retention was significantly affected by Rosiglitazone. Rosiglitazone significantly delayed the formation of tight junctions (TJs); 24 h after CS, however, there were no apparent differences between control group and Rosiglitazone group; the development of transepithelial electrical resistance (TER) was significantly disturbed in Rosiglitazone group. This study shows Rosiglitazone may affect the development and maintenance of apical domains and the formation of TJs disturbs apical protein delivery to the plasma membrane, eventually leading to the abnormal apico-basal polarity, which affects lumen formation in MDCKII cells.

Saccharomonospora xiaoerkulensis sp. nov., isolated from lake sediment.

A novel actinomycete, strain TRM 41495T, was isolated from lake sediment of Xiaoerkule lake in Xinjiang province, China, and was examined using a polyphasic approach. Strain TRM 41495T was aerobic, Gram-stain-positive, growing best on ISP medium 7 with abundant white aerial mycelium formed and brown soluble pigments produced. The optimum NaCl concentration for growth was 3.0 % (w/v), and the optimum temperature for growth was 37 °C. On the basis of 16S rRNA gene sequence analysis, strain TRM 41495T was shown to belong to the genus Saccharomonospora with a sequence similarity of 97.50 % with the most closely related species, Saccharomonospora xinjiangensis. The organism had chemical and morphological features typical of the genus Saccharomonospora. The cell wall of strain TRM 41495T contained meso-diaminopimelic acid, and galactose, arabinose, ribose and mannose were the major whole-cell sugars. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol and an unknown phosphoglycolipid. The predominant menaquinones were MK-9(H4) and MK-9(H2). The major fatty acids were iso-C16 : 0, C16 : 0, C17 : 1ω6c, anteiso-C17 : 0 and iso-C16 : 1H. The G+C content of the DNA was 72.9 mol%. However, DNA-DNA hybridization studies between strain TRM 41495T and Saccharomonospora xinjiangensis showed only 43.9 % relatedness. Whole-cell sugars, menaquinones and fatty acids differentiate strain TRM 41495T from Saccharomonospora xinjiangensis. On the basis of the polyphasic evidence, strain TRM 41495T represents a novel species of the genus Saccharomonospora, for which the name Saccharomonospora xiaoerkulensis sp. nov. is proposed. The type strain is TRM 41495T (=CCTCC AA 2015038T=KCTC 39727T).

Amycolatopsis salitolerans sp. nov., a filamentous actinomycete isolated from a hypersaline habitat.

A novel actinomycete strain, designated TRM F103(T), was isolated from a hypersaline habitat of the Tarim basin in Xinjiang province, north-west China. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belonged to the genus Amycolatopsis and was most closely related to Amycolatopsis halophila YIM 93223(T) (99.3% 16S rRNA gene sequence similarity). However, DNA-DNA relatedness between these two strains, based on triplicate experiments, was only 31.6%. The isolate contained meso-diaminopimelic acid and ribose, glucose and galactose as the major whole-cell sugars. The predominant menaquinone was MK-8(H(4)). The major fatty acids were iso-C(16:0) and C(16:0). The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine and glucosamine-containing phospholipids. The G+C content of the genomic DNA was 66.4 mol%. The phenotypic data clearly distinguished the isolate from its closest relatives. The combined phylogenetic, chemotaxonomic and phenotypic data indicate that the isolate represents a novel species of the genus Amycolatopsis. The proposed name is Amycolatopsis salitolerans sp. nov., with TRM F103(T) (=JCM 15899(T)=CCTCC AB 208326(T)) as the type strain.

The small GTPase Cdc42 interacts with Niemann-Pick C1-like 1 (NPC1L1) and controls its movement from endocytic recycling compartment to plasma membrane in a cholesterol-dependent manner.

Niemann-Pick C1-like 1 (NPC1L1) is a multi-transmembrane protein that mediates the absorption of dietary and biliary cholesterol through vesicular endocytosis. The subcellular localization of NPC1L1 is regulated by cholesterol. Cholesterol depletion induces the transport of NPC1L1 to plasma membrane (PM) from endocytic recycling compartment that requires MyoVb·Rab11a·Rab11-FIP2 triple complex, and cholesterol-replenishment renders the internalization of NPC1L1 together with cholesterol. Here, we find that GTP-bound Cdc42 interacts with NPC1L1. Cholesterol depletion regulates the activation of Cdc42 and enhances NPC1L1-Cdc42 interaction. Overexpression of constitutive GTP-bound Cdc42 mutant form or knockdown of Cdc42 inhibits the transport of NPC1L1 to the PM and disturbs the cholesterol-regulated binding of NPC1L1 to Rab11a, MyoVb, and actin. Knockdown of Cdc42 downstream effectors N-WASP or Arp3 also leads to the similar results. In liver-specific Cdc42 knock-out (Cdc42 LKO) mice, NPC1L1 fails to localize to bile canaliculi, and the biliary cholesterol cannot be efficiently reabsorbed. These results indicate that Cdc42 controls the cholesterol-regulated transport and localization of NPC1L1, and plays a role in cholesterol absorption.

Impact of inter-subunit interactions on the dimeric arginine kinase activity and structural stability.

Arginine kinase (AK) is a key enzyme for cellular energy metabolism, catalyzing the reversible phosphoryl transfer from phosphoarginine to ADP in invertebrates. In this study, the inter-subunit hydrogen bonds between the Q53 and D200 and between D57 and D200 were disrupted to explore their roles in the activity and structural stability of Stichopus japonicus (S. japonicus) AK. Mutating Q53 and/or D57 to alanine (A) can cause pronounced loss of activity and substrate synergism, and cause distinct conformational changes. Spectroscopic experiments indicated that mutations destroying the inter-subunit hydrogen bonds impaired the structure of dimer AK, and resulted in a partially unfolded state. The inability to fold to the functional compact state made the mutants prone to be inactivated and aggregate under environmental stresses. Restoring hydrogen bonds in Q53E and D57E mutants could rescue the loss of activity and substrate synergism, and conformational changes. All those results suggested that the inter-subunit interactions played a key role in keeping the activity, substrate synergism and structural stability of dimer AK. The result herein may provide a clue in understanding the folding and self-assembly processes of oligomeric proteins.

Glycomyces halotolerans sp. nov., a novel actinomycete isolated from a hypersaline habitat in Xinjiang, China.

A novel actinomycete strain, designated TRM 40137(T), was isolated from a hypersaline habitat in Xinjiang Province, north-west China, and subjected to a polyphasic taxonomic study. The strain was aerobic, Gram-positive and the optimum NaCl concentration for growth was 4-5% (w/v). Phylogenetic analysis showed that strain TRM 40137(T) has a 16S rRNA gene sequence similarity of 95.02% with the described species Glycomyces sambucus E71(T) and can be distinguished from all previously described representatives of the genus Glycomyces. The whole-cell sugar pattern consisted of xylose and galactose. The predominant menaquinone was MK-10(H(2)) and the major fatty acids were anteiso-C15:0 and anteiso-C17:0. The phospholipid pattern consists of phosphatidylglycerol, diphosphatidylglycerol, three unknown aminophospholipids and two unknown phospholipids. The G+C content of the genomic DNA was 68.8 mol%. A novel species Glycomyces halotolerans sp. nov. is proposed, with strain TRM 40137(T) (=CCTCC AA 2010013(T) = KCTC 19988(T)) as the type strain of G. halotolerans.

RNase9, an androgen-dependent member of the RNase A family, is specifically expressed in the rat epididymis.

Members of the RNase superfamily participate in a diverse array of biological processes, including RNA degradation, antipathogen activities, angiogenesis, and digestion. In the present study, we cloned the rat RNase9 gene by in silico methods and genome walking based on homology to the Macaca mulatta (rhesus monkey) epididymal RNase9. The gene is located on chromosome 15p14, spanning two exons, and is clustered with other members of the RNase A superfamily. It contains 1279 bp and encodes 182 amino acids, including a 24-amino acid signal peptide, and it has unique features known from other RNases. Unlike those other members, the rat RNase9 mRNA was specifically expressed in the epididymis, especially in the caput and corpus, and exhibited an androgen-dependent expression pattern but was downregulated in an epididymitis animal model. The RNASE9 was expressed in a principal cell-specific pattern. Interestingly, most of the principal cells in the caput expressed the RNASE9; however, in the distal caput, the principal cells showed a checkerboard-like pattern of immunoreactivity. We also observed that the RNASE9 was bound on the acrosomal domain of sperm. Its potential roles in sperm maturation are discussed.