A gain-of-function variation in PLCG1 causes a new immune dysregulation disease.

BACKGROUND: Phospholipase C (PLC) γ1 is a critical enzyme regulating nuclear factor-κB (NF-κB), extracellular signal-related kinase, mitogen-activated protein kinase, and nuclear factor of activated T cells signaling pathways, yet germline PLCG1 mutation in human disease has not been reported. OBJECTIVE: We aimed to investigate the molecular pathogenesis of a PLCG1 activating variant in a patient with immune dysregulation. METHODS: Whole exome sequencing was used to identify the patient's pathogenic variants. Bulk RNA sequencing, single-cell RNA sequencing, quantitative PCR, cytometry by time of flight, immunoblotting, flow cytometry, luciferase assay, IP-One ELISA, calcium flux assay, and cytokine measurements in patient PBMCs and T cells and COS-7 and Jurkat cell lines were used to define inflammatory signatures and assess the impact of the PLCG1 variant on protein function and immune signaling. RESULTS: We identified a novel and de novo heterozygous PLCG1 variant, p.S1021F, in a patient presenting with early-onset immune dysregulation disease. We demonstrated that the S1021F variant is a gain-of-function variant, leading to increased inositol-1,4,5-trisphosphate production, intracellular Ca2+ release, and increased phosphorylation of extracellular signal-related kinase, p65, and p38. The transcriptome and protein expression at the single-cell level revealed exacerbated inflammatory responses in the patient's T cells and monocytes. The PLCG1 activating variant resulted in enhanced NF-κB and type II interferon pathways in T cells, and hyperactivated NF-κB and type I interferon pathways in monocytes. Treatment with either PLCγ1 inhibitor or Janus kinase inhibitor reversed the upregulated gene expression profile in vitro. CONCLUSIONS: Our study highlights the critical role of PLCγ1 in maintaining immune homeostasis. We illustrate immune dysregulation as a consequence of PLCγ1 activation and provide insight into therapeutic targeting of PLCγ1.

Iron-regulated assembly of the cytosolic iron-sulfur cluster biogenesis machinery.

The cytosolic iron-sulfur (Fe-S) cluster assembly (CIA) pathway delivers Fe-S clusters to nuclear and cytosolic Fe-S proteins involved in essential cellular functions. Although the delivery process is regulated by the availability of iron and oxygen, it remains unclear how CIA components orchestrate the cluster transfer under varying cellular environments. Here, we utilized a targeted proteomics assay for monitoring CIA factors and substrates to characterize the CIA machinery. We find that nucleotide-binding protein 1 (NUBP1/NBP35), cytosolic iron-sulfur assembly component 3 (CIAO3/NARFL), and CIA substrates associate with nucleotide-binding protein 2 (NUBP2/CFD1), a component of the CIA scaffold complex. NUBP2 also weakly associates with the CIA targeting complex (MMS19, CIAO1, and CIAO2B) indicating the possible existence of a higher order complex. Interactions between CIAO3 and the CIA scaffold complex are strengthened upon iron supplementation or low oxygen tension, while iron chelation and reactive oxygen species weaken CIAO3 interactions with CIA components. We further demonstrate that CIAO3 mutants defective in Fe-S cluster binding fail to integrate into the higher order complexes. However, these mutants exhibit stronger associations with CIA substrates under conditions in which the association with the CIA targeting complex is reduced suggesting that CIAO3 and CIA substrates may associate in complexes independently of the CIA targeting complex. Together, our data suggest that CIA components potentially form a metabolon whose assembly is regulated by environmental cues and requires Fe-S cluster incorporation in CIAO3. These findings provide additional evidence that the CIA pathway adapts to changes in cellular environment through complex reorganization.

[Clinical characteristics and genetic analysis of a case with adult neuronal ceroid lipofuscinosis type 7 due to variant of MFSD8 gene].

OBJECTIVE: To explore the clinical characteristics and genetic variants in a patient with adult ceroid lipofuscinosis neuronal type 7 (ACLN7). METHODS: A female patient diagnosed with ACLN7 in Henan Provincial People's Hospital in June 2021 was selected as the study subject. Clinical data, auxiliary examination and result of genetic testing were retrospectively analyzed. RESULTS: The patient, a 39-year-old female, has mainly presented progressive visual loss, epilepsy, cerebellar ataxia and mild cognitive decline. Neuroimaging analysis has revealed generalized brain atrophy, prominently cerebellum. Fundus photography has revealed retinitis pigmentosa. Ultrastructural skin examination has revealed granular lipofuscin deposits in the periglandular interstitial cells. Whole exome sequencing revealed that she has harbored compound heterozygous variants of the MSFD8 gene, namely c.1444C>T (p.R482*) and c.104G>A (p.R35Q). Among these, c.1444C>T (p.R482*) was a well established pathogenic variant, while c.104G>A (p.R35Q) was a missense variant unreported previously. Sanger sequencing confirmed that the daughter, son and elder brother of the proband have respectively carried heterozygous c.1444C>T (p.R482*), c.104G>A (p.R35Q), and c.104G>A (p.R35Q) variants of the same gene. The family has therefore fit with the autosomal recessive inheritance pattern of the CLN7. CONCLUSION: Compared with previously reported cases, this patient has the latest onset of the disease with a non-lethal phenotype. Her clinical features have involved multiple systems. Cerebellar atrophy and fundus photography may be indicative of the diagnosis. The c.1444C>T (p.R482*) and c.104G>A (p.R35Q) compound heterozygous variants of the MFSD8 gene probably underlay the pathogenesis in this patient.

A nicotinamide phosphoribosyltransferase-GAPDH interaction sustains the stress-induced NMN/NAD+ salvage pathway in the nucleus.

All cells require sustained intracellular energy flux, which is driven by redox chemistry at the subcellular level. NAD+, its phosphorylated variant NAD(P)+, and its reduced forms NAD(P)/NAD(P)H are all redox cofactors with key roles in energy metabolism and are substrates for several NAD-consuming enzymes (e.g. poly(ADP-ribose) polymerases, sirtuins, and others). The nicotinamide salvage pathway, constituted by nicotinamide mononucleotide adenylyltransferase (NMNAT) and nicotinamide phosphoribosyltransferase (NAMPT), mainly replenishes NAD+ in eukaryotes. However, unlike NMNAT1, NAMPT is not known to be a nuclear protein, prompting the question of how the nuclear NAD+ pool is maintained and how it is replenished upon NAD+ consumption. In the present work, using human and murine cells; immunoprecipitation, pulldown, and surface plasmon resonance assays; and immunofluorescence, small-angle X-ray scattering, and MS-based analyses, we report that GAPDH and NAMPT form a stable complex that is essential for nuclear translocation of NAMPT. This translocation furnishes NMN to replenish NAD+ to compensate for the activation of NAD-consuming enzymes by stressful stimuli induced by exposure to H2O2 or S-nitrosoglutathione and DNA damage inducers. These results indicate that by forming a complex with GAPDH, NAMPT can translocate to the nucleus and thereby sustain the stress-induced NMN/NAD+ salvage pathway.

Watch out for neuromyelitis optica spectrum disorder after inactivated virus vaccination for COVID-19.

With recent availability of COVID-19 vaccine, post-vaccination neurological complications had been occasionally reported. Here, we reported for the first time a case of neuromyelitis optica spectrum disorder (NMOSD) that developed after the first dose of inactivated virus vaccine for COVID-19. The patient developed mild fever, vomiting, diarrhea, and cough after receiving the first dose of inactivated virus vaccine. Two months later, she experienced dizziness and unsteady walking. MRI scanning of the brain revealed lesions in area postrema and bilateral hypothalamus, typical for NMOSD. Serum antibodies for AQP4, ANA, SSA, SSB, Ro-52, and p-ANCA were positive. The patient was diagnosed as AQP4-positive NMOSD with coexisting systemic autoimmunity. After treatment with methylprednisolone (500 mg for 5 days), symptoms were greatly relieved. As NMOSD is seriously harmful and curative, it is important to be aware of the NMOSD symptoms after vaccination. Cautions should be given for those with preexisting systemic autoimmune abnormalities in vaccination for COVID-19.

Rapid Visual Detection Method for Barley Yellow Mosaic Virus Using Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP).

Barley yellow mosaic disease, caused mainly by Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus, is a devastating disease of barley and is a threat to Eurasian barley production. Early detection is essential for effective management of the pathogens and to assure food security. In this study, a simple, rapid, specific, sensitive, and visual method was developed to detect BaYMV using loop-mediated isothermal amplification (LAMP). Two pairs of oligonucleotide primers (inner and outer primers) were designed to amplify the gene encoding the coat protein of BaYMV. The optimal conditions for the LAMP method were determined, and a one-step reverse transcription (RT)-LAMP method was also developed. Subsequently, the fastest processing time for RT-LAMP was determined. Among eight plant viruses examined using the LAMP method, only BaYMV was detectable, suggesting that the assay was highly specific. The RT-LAMP method was 10 times more sensitive than the RT-PCR method in the sensitivity test. To further shorten the virus detection process, a dye was added to the RT-LAMP products, and positive reactions were simply read by the naked eye via a color change (from orange to light green) under visible light. Barley samples from the middle and lower reaches of the Yangtze River basin, where BaYMV broke out very seriously in 1970s, were detected by the newly established RT-LAMP method. The results showed that all samples were positive for BaYMV, indicating the potential risk of the virus in these areas. This newly established LAMP/RT-LAMP method could be a promising tool for barley protection and food security control.

Studies on the chemical constituents and quality evaluation of Rosa cymosa Tratt. root.

Nowadays, the root of Rose cymosa Tratt. (Rosaceae) is widely used in clinic as one of the sources of Chinese herb medicine Jinyinggen. However, only few studies have been done on its chemical composition and quality control. In this study, 27 monomeric compounds were obtained from the ethanol extract of the roots of R. cymosa Tratt., including two undescribed triterpenes, one of which contains a distinctive contracted five-membered A-ring ursane-type skeleton and the other is a common ursane-type tritepene. Then, triterpenoids, the main components of the R. cymosa root, were qualitatively and quantitatively analyzed by thin-layer chromatography and high-performance liquid chromatography methods. Thin-layer chromatography can identify seven triterpenoids in R. cymosa Tratt. spontaneously. For the high-performance liquid chromatography fingerprint, total of 16 chromatographic peaks were selected as the common peaks of 20 batches of samples, ten of which were identified by reference substances. At the same chromatographic condition, five abundant triterpenoids were quantitatively assayed. R. cymose, as one of the origins of Jinyinggen, was similar to R. laevigata in triterpenoids compounds, which demonstrated that both of them could be used in the clinical medication. These work also laid a foundation for the further research and development of triterpenoids in R. cymosa root.

Metabolomics study of different parts of licorice from different geographical origins and their anti-inflammatory activities.

Glycyrrhiza uralensis Fisch., known as licorice, is one of the most famous traditional Chinese medicines. In this study, we perform a metabolome analysis using liquid chromatography-tandem mass spectrometry to assign bioactive components in different parts of licorice from different geographical origins in Gansu province of China. Sixteen potential biomarkers of taproots from different geographical origins were annotated, such as glycycoumarin, gancaonin Z, licoricone, and dihydroxy kanzonol H mainly exist in the sample of Jiuquan; neoliquiritin, 6'-acetylliquiritin, licochalcone B, isolicoflavonol, glycyrol, and methylated uralenin mainly exist in Glycyrrhiza uralensis from Lanzhou; gancaonin L, uralenin, and glycybridin I mainly exist in licorice from Wuwei for the first time.

Chemical Derivatization of Affinity Matrices Provides Protection from Tryptic Proteolysis.

The enrichment of biotinylated proteins using immobilized streptavidin has become a staple methodology for affinity purification-based proteomics. Many of these workflows rely upon tryptic digestion to elute streptavidin-captured moieties from the beads. The concurrent release of high amounts of streptavidin-derived peptides into the digested sample, however, can significantly hamper the effectiveness of downstream proteomic analyses by increasing the complexity and dynamic range of the mixture. Here, we describe a strategy for the chemical derivatization of streptavidin that renders it largely resistant to proteolysis by trypsin and thereby dramatically reduces the amount of streptavidin contamination in the sample. This rapid and robust approach improves the effectiveness of mass spectrometry-based characterization of streptavidin-purified samples making it broadly useful for a wide variety of applications. In addition, we show that this chemical protection strategy can also be applied to other affinity matrices including immobilized antibodies against HA epitopes.

Decoding the Interactions Regulating the Active State Mechanics of Eukaryotic Protein Kinases.

Eukaryotic protein kinases regulate most cellular functions by phosphorylating targeted protein substrates through a highly conserved catalytic core. In the active state, the catalytic core oscillates between open, intermediate, and closed conformations. Currently, the intramolecular interactions that regulate the active state mechanics are not well understood. Here, using cAMP-dependent protein kinase as a representative model coupled with biochemical, biophysical, and computational techniques, we define a set of highly conserved electrostatic and hydrophobic interactions working harmoniously to regulate these mechanics. These include the previously identified salt bridge between a lysine from the ß3-strand and a glutamate from the αC-helix as well as an electrostatic interaction between the phosphorylated activation loop and αC-helix and an ensemble of hydrophobic residues of the Regulatory spine and Shell. Moreover, for over three decades it was thought that the highly conserved ß3-lysine was essential for phosphoryl transfer, but our findings show that the ß3-lysine is not required for phosphoryl transfer but is essential for the active state mechanics.

Rapid visual detection of lily mottle virus using a loop-mediated isothermal amplification method.

Lily mottle virus (LMoV; genus Potyvirus, family Potyviridae) infects plants of the genus Lilium, causing a reduction in flower and bulb quality. A rapid and sensitive loop-mediated isothermal amplification (LAMP) assay was developed to detect the coat protein gene of LMoV. This LAMP method was highly specific for LMoV, with no cross-reaction with other lily viruses. The sensitivity of LMoV using the LAMP assay was 100 times more sensitive than that using conventional polymerase chain reaction. A reverse transcription LAMP (RT-LAMP) was then successfully applied to detect LMoV RNA. The newly established LAMP and one-step RT-LAMP provide an alternative method for detecting LMoV in lily plants.

[Quantitative determination of febrifugine by proton nuclear magnetic resonance spectroscopy with internal standard method].

A quantitative nuclear magnetic resonance method(qNMR) was established for determination of the absolute content of febrifugine. Proton nuclear magnetic resonance spectroscopy of febrifugine was obtained in DMSO-d6 with hydroquinone as the internal standard substance on a Bruker Ascend 600 MHz superconducting nuclear resonance spectrometer at 298 K. The specific parameters were as follows: the observing frequency was 600 MHz,spectra width was 7 211 Hz, pulse width was 9.70 µs, pulse sequence was zg30,scan times was 32 and relaxation time was 2 s. The proton signal peaked at δ 7.71 for febrifugine and δ 6.55 for hydroquinone were selected as the quantification peaks. Linear regression of quantitative peak area ratio of febrifugine-hydroquinone versus their mass ratio yielded a correlation coefficient of 0.999 6 and a regression equation of Y=0.083 3X+0.008 6．The linear range of febrifugine was 2.17-17.07 g·L⁻¹,the precision RSD was 0.78%(n=6),the repeatability RSD was 1.2%(n=6),and the contents of three batches of febrifugine sample were 94.91%,95.09% and 95.52%,respectively. The content of febrifugine was 96.44% determined by high performance liquid chromatography(HPLC). The relative error of the content of febrigugine determinted by qNMR and HPLC methods was 1.27%. The results showed that the internal standard method of proton nuclear magnetic resonance spectroscopy could be used to determine the absolute content of febrifugine.

Dietary safety assessment of genetically modified rice EH rich in ß-carotene.

This 90-day study aimed to assess the dietary safety of transgenic rice EH which is rich in ß-carotene. Two experimental groups of Sprague-Dawley rats were fed diets containing 45% rice flour of Zhonghua 11 rice and transgenic rice EH rich in ß-carotene, respectively. The reference group was fed a diet containing standard feed nutrition. During the trial period, each rat was weighed and the food intake was recorded twice a week. Their behaviors were observed daily. In the end, blood samples were obtained from all anesthetized rats to measure the hematologic and serum chemistry indicators. Growth performance, anatomy and pathology of all organs in each group were analyzed. Although a few parameters were found to be statistically significantly different across groups, they were within the normal reference range for this breed and age of rats. Therefore, the changes were not considered to be diet related. The results revealed that the transgenic rice EH rich in ß-carotene was as nutritious as Zhonghua 11 rice and showed a lack of biologically meaningful unintended effects.

[Qualitative and quantitative analysis of Evodiae Fructus based on the UPLC technology].

An UPLC method was developed for the studies of fingerprint and quantification of multi-components for Evodiae Fructus. The chromatographic separation was performed on a C18 column (2.1 mm×50 mm,1.7 µm) with mobile phase of 0.2% formic acid-acetonitrile and 0.2% formic acid-water in gradient mode, and the detection wavelength was set at 320 nm．Dehydroevodiamine was used as the reference peak, there were 24 common peaks in the fingerprint of 29 samples were detected, and among them 10 chromatographic peaks were identified with the reference substance and they were neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, hyperin, isorhamnetin-3-O-ß-D-rutinoside, dehydroevodiamine, evodiamine, rutaecarpine, evocarpine and dihydroevocarpine. The fingerprint data was evaluated with similarity evaluation system for chromatographic fingerprint of traditional Chinese medicine (Version 2008A), and the similarity of 19 batches of Evodiae Fructus was greater than 0.9 in the 29 samples. In addition, 9 components including neochlorogenic acid, chlorogenic acid, hyperin, isorhamnetin-3-O-ß-D-rutinoside, dehydroevodiamine, evodiamine, rutaecarpine, evocarpine and dihydroevocarpine were simultaneously determined at the same chromatographic conditions, whose peak area integral values showed good linear relationship at the range of 0.000 46-0.138, 0.000 146-0.175, 0.000 412-0.124, 0.000 448-0.134, 0.000 452-0.136, 0.003 38-0.169, 0.000 44-0.132, 0.001 07-0.128, 0.001 71-0.128, respectively. Their average recoveries were 100.3%, 100.4%, 101.6%, 97.51%, 102.9%, 101.4%, 103.8%, 104.0%, 95.99%, and RSD were 2.4%, 2.0%, 3.0%, 0.80%, 1.9%, 2.1%, 1.1%, 2.2%, 2.4%, respectively. The established UPLC method not only realized the full separation of all chemical constituents of Evodiae Fructus within 20 minutes, but also achieved the chromatographic fingerprint determination and simultaneous multi-components determination of Evodiae Fructus at the same chromatographic conditions. Compared with other methods in literatures, the method has the following characteristics of strong specificity, good separation, high purity of chromatographic peaks, simplity and feasibility, which provides better means for the simultaneous qualitative and quantitative analysis of Evodiae Fructus.

Elevated temperature affects the expression of signaling molecules in quail testes meiosis I prophase, but spermatogenesis remains normal.

Spermatogenesis in eukaryotes is a process that occurs within a very narrow temperature threshold, typically not exceeding 36 °C. SPO11 was isolated from the temperature-sensitive mutant receptor of Saccharomyces cerevisiae and is thought to be the only protein that functions during meiosis. This suggested that SPO11 may be the key protein that influenced the temperature of spermatogenesis not exceeding 36 °C. Elevated temperatures typically damage the spermatogenic cells. Birds have a core body temperature of 41-42 °C, and their testis are located inside their bodies, providing an alternative perspective to investigate the potential impact of temperature threshold on spermatogenesis. The objective of this study was to ascertain whether elevated ambient temperatures affect spermatogenesis in birds and whether SPO11 is the key gene affecting the temperature threshold for spermatogenesis. STRA8, SCP3, SPO11, γ-H2AX, and RAD51 were all crucial components in the process of meiotic initiation, synapsis, DNA double-strand break (DSB) induction, homologous chromosome crossover recombination, and repair of DSB. In this study, 39-day-old Japanese quail were subjected to heat stress (HS) at 38 °C for 8 h per day for 3 (3d HS) and 13 (13d HS) consecutive days and analyzed the expression of meiotic signaling molecules (STRA8, SCP3, SPO11, γ-H2AX, and RAD51) using molecular biology techniques, including Immunohistochemistry (IHC), Western Blot (WB), and Real-time Quantitative Polymerase Chain Reaction (qRT-PCR). We found that spermatogenesis was normal in both groups exposed to HS. Meiotic signaling molecules were expressed normally in the 3d HS group. All detected signaling molecules were normally expressed in the 13d HS group, except for SPO11, which showed a significant increase in expression, indicating that SPO11 was temperature-sensitive. We examined the localized expression of each meiotic signaling molecule in quail testis, explored the temperature sensitivity of SPO11, and determined that quail testis can undergo normal spermatogenesis at ambient temperatures exceeding 36 °C. This study concluded that SPO11 is not the key protein influencing spermatogenesis in birds. These findings enhance our understanding of avian spermatogenesis.

PGC-1α regulates endoplasmic reticulum stress in IPF-derived fibroblasts.

Idiopathic pulmonary fibrosis (IPF) is considered to be associated with aging. Both ER stress and the unfolded protein response (UPR) have been associated with pulmonary fibrosis via key mechanisms including AEC apoptosis, EMT, altered myofibroblast differentiation, and M2 macrophage polarization. A relationship between ER stress and aging has also been demonstrated in vitro, with increased p16 and p21 levels seen in lung epithelial cells of older IPF patients. The mechanism underlying ER stress regulation of IPF fibroblasts is still unclear. In this study, we aimed to delineate ER stress regulation in IPF-derived fibroblasts. Here, we found that ER stress markers (p-eIF2α, p-IREα, ATF6) and fibrosis markers (α-SMA and Collagen-I) were significantly increased in lung tissues of IPF patients and bleomycin-induced mouse models. Notably, the expression of PGC-1α was decreased in fibroblasts. In vivo experiments were designed using an AAV-6 vector mediated conditional PGC-1α knockout driven by a specific α-SMA promoter. Ablation of PGC-1α expression in fibroblasts promoted ER stress and supported the development of pulmonary fibrosis in a bleomycin-induced mouse model. In another experimental group, mice with conditional knockout of PGC-1α in fibroblasts and injected intraperitoneally with 4-PBA (an endoplasmic reticulum stress inhibitor) were protected from lung fibrosis. We further constructed an AAV-6 vector mediated PGC-1α overexpression model driven by a specific Collagen-I promoter. Overexpression of PGC-1α in fibroblasts suppressed ER stress and attenuated development of pulmonary fibrosis in bleomycin-induced mouse models. Taken together, this study identified PGC-1α as a promising target for developing novel therapeutic options for the treatment of lung fibrosis.

ADA2 deficiency (DADA2) misdiagnosed as systemic onset juvenile idiopathic arthritis in a child carrying a novel compound heterozygous ADA2 mutation: a case report.

Background: The deficiency of adenosine deaminase 2 (DADA2) is caused by an autosomal recessive bi-allelic loss-of-function mutation in the adenosine deaminase 2 (ADA2) gene. DADA2 is a monogenic inherited autoinflammatory disorder characterized by early-onset vasculopathy for which the symptoms range from skin lesions to very severe multiorgan involvement, including life-threatening ischemia and/or hemorrhagic strokes. Owing to the diversity of clinical presentation and the absence of suggestive features, differentiating DADA2 from other inflammatory disorders in the early stages of disease presentation is difficult. Here, we describe the case of a 3-year-old boy who had been misdiagnosed for nearly 2 years before he was definitively diagnosed with DADA2. Case Description: A previously healthy 3-year-old boy was initially diagnosed with systemic onset juvenile idiopathic arthritis (soJIA) owing to recurrent unprovoked fever and elevated acute phase reactants. He developed intractable hypertension during treatment, which his doctor considered an adverse drug reaction. Monogenic inherited autoinflammatory disorders were not suspected until the patient developed intestinal perforation and ensuing recurrent abdominal pain that coincided with fever. Gene sequence analysis revealed a novel compound heterozygous mutation in ADA2. The ADA2 enzyme activity was almost completely lost in the patient. Conclusions: The broad phenotypic spectrum of DADA2 makes early diagnosis challenging. DADA2 should be considered in case of early-onset vasculitis, which is the most common phenotype of DADA2. Early identification and treatment will result in significant improvement of the disease.

Rapid, visual and highly sensitive sexing of bovine embryos by recombinase polymerase amplification with CFI staining.

Early bovine embryo sexing both increases the number of offspring of the desired sex, and reduces the subsequent costs of processing unwanted offspring of the opposite sex. The need for cattle of different sexes varies from industry to industry, and a range of tools have been set up to meet this need, but most are energy- and time-consuming, hence it is important to establish a fast and convenient method for bovine embryo determination. Herein, we established a recombinase polymerase amplification (RPA) method combined with CFI dye (RPA-CFI) for sexing of bovine embryos. The assay is highly sensitive, specific, rapid and simple; it can be carried out in only 5 min at 37 °C in a metal bath, and results are visualised using a fluorescent colorimeter. Highly specific male-female common and male-specific primers were designed based on the 1399 bp repeating unit of bovine 1.715 satellite DNA and the male-specific S4 repeating sequence, respectively. The limit of detection (LOD) of RPA-CFI with male-female common primers was 1 pg/µL, and the LOD with male-specific primers was 2 pg/µL. RPA-CFI could determine the sex of bovine embryos from only two cells. This is the first report using RPA-CFI for sex determination of bovine embryos. The assay could be applied to other economically important animals to improve efficiency in livestock industries. Additionally, the assay could relieve pressure on food demand due to human population growth, and contribute to economic development of global stockbreeding.