HP1BP3, a Chromatin Retention Factor for Co-transcriptional MicroRNA Processing.

Recent studies suggest that the microprocessor (Drosha-DGCR8) complex can be recruited to chromatin to catalyze co-transcriptional processing of primary microRNAs (pri-miRNAs) in mammalian cells. However, the molecular mechanism of co-transcriptional miRNA processing is poorly understood. Here we find that HP1BP3, a histone H1-like chromatin protein, specifically associates with the microprocessor and promotes global miRNA biogenesis in human cells. Chromatin immunoprecipitation (ChIP) studies reveal genome-wide co-localization of HP1BP3 and Drosha and HP1BP3-dependent Drosha binding to actively transcribed miRNA loci. Moreover, HP1BP3 specifically binds endogenous pri-miRNAs and facilitates the Drosha/pri-miRNA association in vivo. Knockdown of HP1BP3 compromises pri-miRNA processing by causing premature release of pri-miRNAs from the chromatin. Taken together, these studies suggest that HP1BP3 promotes co-transcriptional miRNA processing via chromatin retention of nascent pri-miRNA transcripts. This work significantly expands the functional repertoire of the H1 family of proteins and suggests the existence of chromatin retention factors for widespread co-transcriptional miRNA processing.

TAF11 Assembles the RISC Loading Complex to Enhance RNAi Efficiency.

Assembly of the RNA-induced silencing complex (RISC) requires formation of the RISC loading complex (RLC), which contains the Dicer-2 (Dcr-2)-R2D2 complex and recruits duplex siRNA to Ago2 in Drosophila melanogaster. However, the precise composition and action mechanism of Drosophila RLC remain unclear. Here we identified the missing factor of RLC as TATA-binding protein-associated factor 11 (TAF11) by genetic screen. Although it is an annotated nuclear transcription factor, we found that TAF11 also associated with Dcr-2/R2D2 and localized to cytoplasmic D2 bodies. Consistent with defective RLC assembly in taf11(-/-) ovary extract, we reconstituted the RLC in vitro using the recombinant Dcr-2-R2D2 complex, TAF11, and duplex siRNA. Furthermore, we showed that TAF11 tetramer facilitates Dcr-2-R2D2 tetramerization to enhance siRNA binding and RISC loading activities. Together, our genetic and biochemical studies define the molecular nature of the Drosophila RLC and elucidate a cytoplasmic function of TAF11 in organizing RLC assembly to enhance RNAi efficiency.

Autoantigen La promotes efficient RNAi, antiviral response, and transposon silencing by facilitating multiple-turnover RISC catalysis.

The effector of RNA interference (RNAi) is the RNA-induced silencing complex (RISC). C3PO promotes the activation of RISC by degrading the Argonaute2 (Ago2)-nicked passenger strand of duplex siRNA. Active RISC is a multiple-turnover enzyme that uses the guide strand of siRNA to direct the Ago2-mediated sequence-specific cleavage of complementary mRNA. How this effector step of RNAi is regulated is currently unknown. Here, we used the human Ago2 minimal RISC system to purify Sjögren's syndrome antigen B (SSB)/autoantigen La as an activator of the RISC-mediated mRNA cleavage activity. Our reconstitution studies showed that La could promote multiple-turnover RISC catalysis by facilitating the release of cleaved mRNA from RISC. Moreover, we demonstrated that La was required for efficient RNAi, antiviral defense, and transposon silencing in vivo. Taken together, the findings of C3PO and La reveal a general concept that regulatory factors are required to remove Ago2-cleaved products to assemble or restore active RISC.

Attenuation of Acute Phase Injury in Rat Intracranial Hemorrhage by Cerebrolysin that Inhibits Brain Edema and Inflammatory Response.

The outcome of intracerebral hemorrhage (ICH) is mainly determined by the volume of the hemorrhage core and the secondary brain damage to penumbral tissues due to brain swelling, microcirculation disturbance and inflammation. The present study aims to investigate the protective effects of cerebrolysin on brain edema and inhibition of the inflammation response surrounding the hematoma core in the acute stage after ICH. The ICH model was induced by administration of type VII bacterial collagenase into the stratum of adult rats, which were then randomly divided into three groups: ICH + saline; ICH + Cerebrolysin (5 ml/kg) and sham. Cerebrolysin or saline was administered intraperitoneally 1 h post surgery. Neurological scores, extent of brain edema content and Evans blue dye extravasation were recorded. The levels of pro-inflammatory factors (IL-1ß, TNF-α and IL-6) were assayed by Real-time PCR and Elisa kits. Aquaporin-4 (AQP4) and tight junction proteins (TJPs; claudin-5, occludin and zonula occluden-1) expression were measured at multiple time points. The morphological and intercellular changes were characterized by Electron microscopy. It is found that cerebrolysin (5 ml/kg) improved the neurological behavior and reduced the ipsilateral brain water content and Evans blue dye extravasation. After cerebrolysin treated, the levels of pro-inflammatory factors and AQP4 in the peri-hematomal areas were markedly reduced and were accompanied with higher expression of TJPs. Electron microscopy showed the astrocytic swelling and concentrated chromatin in the ICH group and confirmed the cell junction changes. Thus, early cerebrolysin treatment ameliorates secondary injury after ICH and promotes behavioral performance during the acute phase by reducing brain edema, inflammatory response, and blood-brain barrier permeability.

[Mechanical thrombectomy with the Solitaire AB device in acute ischemic stroke of posterior circulation: a series of 17 cases].

OBJECTIVE: To evaluate the efficacy and safety of mechanical thrombectomy with the Solitaire AB device in recanalization of patients with acute ischemic stroke of posterior circulation. METHODS: The clinical data of 17 consecutive patients with acute ischemic stroke of posterior circulation, treated with the Solitaire AB device from August 2011 to August 2015 in Department of Neurosurgery, the Military General Hospital of Beijing People's Liberation Army, were extracted and then retrospectively analyzed. There were 12 male and 5 female patients with a median age of 60 years (ranging from 44 to 75 years). Among them, 8 cases occluded in basilar artery, 4 cases occluded in vertebral artery and 5 cases occluded in vertebral plus basilar artery. Recanalization rate as well as complications after treatment were analysized. Also, neurological functions of the patients before and after treatment, measured by National Institute of Health stroke scale (NIHSS) score, were compared via t test and the clinical outcomes were assessed by modified Rankin score (mRS) at 90 days after treatment. RESULTS: Fifteen patients resulted in successfully recanalization, and 2 cases failed both of whose onset to sheath time were above 7.5 hours. The NIHSS score at 7 days was 11±10, which was significantly decreased compared to the admission NIHSS score 17±5 (t=2.949, P=0.009). No symptomatic intracranial hemorrhage case was found after thrombectomy. At 90 days, one patient died(mRS 6), one patient seriously disabled (mRS 5), two patients moderately seriously disabled (mRS 4), four patients resulted in moderate outcome (mRS 3) and the other 9 patients achieved good outcome (mRS 0 to 2). The dead and seriously disabled cases were both due to failure in recanalization. Two moderately seriously disabled cases were probably attributed to their severe admission condition (NIHSS >20) and prolonged time (onset to sheath time >6 hours). CONCLUSION: Mechanical thrombectomy with the Solitaire AB device contributes to a high rate of recanalization with a low probability of complication and improves functional outcome in patients with acute ischemic stroke of posterior circulation.

Ultra-early versus delayed coil treatment for ruptured poor-grade aneurysm.

INTRODUCTION: The timing of definitive aneurysm treatment (coiling or clipping) in poor-grade (Hunt-Hess IV or V) subarachnoid haemorrhage (SAH) patients has been a controversial topic. The purpose of this retrospective study was to analyse whether ultra-early coiling of ruptured intracranial aneurysms improves the clinical outcomes of poor-grade SAH patients. METHODS: The records of patients with aneurysmal SAH who were treated with endovascular coiling were retrieved. The patients were classified into two groups: group A (patients coiled within 24 h of SAH) and group B (patients coiled ≥ 24 h after SAH). For each group, the patient demographics, Fisher grade, aneurysm characteristics and clinical outcomes were recorded. Outcomes were measured at 6 months using the modified Rankin Scale (mRS). RESULTS: Thirty-one patients were coiled within 24 h of SAH (group A), and fourteen patients were coiled ≥24 h after SAH (group B). Groups A and B had similar clinical and angiographic characteristics. The clinical outcomes showed that a total of 58.1% of the patients (18 of 31) in group A were independent (mRS 0-2) compared with 21.4% of the patients (3 of 14) in group B (P = .028). Univariate analysis demonstrated that ultra-early coiling (P = .028) proved to be an independent predictor of better clinical outcomes (mRS 0-2). CONCLUSIONS: Ultra-early (<24 h after SAH) coiling of ruptured aneurysms was associated with improved clinical outcomes compared to coiling at ≥24 h in poor-grade SAH patients. Larger, prospective studies are required to adequately assess the outcome differences between these two groups.

Sjogren syndrome antigen B (SSB)/La promotes global microRNA expression by binding microRNA precursors through stem-loop recognition.

MicroRNAs (miRNA) control numerous physiological and pathological processes. Typically, the primary miRNA (pri-miRNA) transcripts are processed by nuclear Drosha complex into ~70-nucleotide stem-loop precursor miRNAs (pre-miRNA), which are further cleaved by cytoplasmic Dicer complex into ~21-nucleotide mature miRNAs. However, it is unclear how nascent pre-miRNAs are protected from ribonucleases, such as MCPIP1, that degrade pre-miRNAs to abort miRNA production. Here, we identify Sjögren syndrome antigen B (SSB)/La as a pre-miRNA-binding protein that regulates miRNA processing in vitro. All three RNA-binding motifs (LAM, RRM1, and RRM2) of La/SSB are required for efficient pre-miRNA binding. Intriguingly, La/SSB recognizes the characteristic stem-loop structure of pre-miRNAs, of which the majority lack a 3' UUU terminus. Moreover, La/SSB associates with endogenous pri-/pre-miRNAs and promotes miRNA biogenesis by stabilizing pre-miRNAs from nuclease (e.g. MCPIP1)-mediated decay in mammalian cells. Accordingly, we observed positive correlations between the expression status of La/SSB and Dicer in human cancer transcriptome and prognosis. These studies identify an important function of La/SSB as a global regulator of miRNA expression, and implicate stem-loop recognition as a major mechanism that mediates association between La/SSB and diverse RNA molecules.

Effects of carotid endarterectomy and carotid artery stenting on high-risk carotid stenosis patients.

OBJECTIVE: To analyze the clinical effects and safety of carotid endarterectomy (CEA) and carotid artery stenting (CAS) in the treatment of high-risk carotid stenosis patients. METHODS: Total 63 patients who underwent CEA or CAS in our hospitals from January 2007 to December 2012 were selected in this study, and were randomly divided into an observation group and a control group. The patients in the observation group were subjected to CAS and those in the control group were subjected to CEA to compare the primary and secondary endpoints of the treatment. RESULTS: The arrival rates of the primary and secondary endpoints were 7.14% and 10.71% respectively in the observation group, while those were 11.43% and 11.43% respectively in the control group. There were no significant differences in the arrival rates of primary and secondary endpoints between the two groups (P>0.05). CONCLUSION: The efficacies and safety of CAS and CEA are similar in treating high-risk carotid stenosis patients.

Comparison between thromboelastography and the conventional coagulation test in detecting effects of antiplatelet agents after endovascular treatments in acute ischemic stroke patients: A STROBE-compliant study.

Antiplatelet agents have been administered to patients with acute ischemic stroke after endovascular therapy. This study was designed to provide initial data to compare thromboelastography (TEG) with the conventional coagulation test (CCT) to analyze the coagulation function of antiplatelet drugs in such patients.The present retrospective cohort study included 240 patients who received endovascular therapy from September 2012 to December 2017. The baseline and clinical characteristics of these patients were collected with respect to TEG (parameters: R, K, maximal amplitude (MA), and α angle) and CCT (parameters: PT, activated partial thromboplastin time (APTT), fibrinogen (FIB), international normalized ratio (INR), and platelet count (PLT)) on day 5 after aspirin and clopidogrel post-endovascular interventions. The correlation and agreement of these 2 detecting methods were analyzed. Additionally, the area under the receiver operating characteristic curve (AUROC) was used to analyze the effectiveness of these 2 methods in detecting unfavorable clinical outcomes, including symptomatic intracranial hemorrhage and early neurological deterioration.The 3 pairs of parameters (R and APTT, K and APTT, and α angle and FIB) were in agreement for identifying hypercoagulability, while R and APTT, K and APTT, K and PLT, and α angle and PLT were in agreement for identifying hypocoagulability. The AUROC of parameter R for detecting symptomatic intracranial hemorrhage was 0.817, while that of parameter FIB for predicting early neurological deterioration was 0.887.Parameter FIB derived from CCT might be advantageous for evaluating early neurological deterioration, while parameter R detected by TEG might be superior for evaluating symptomatic intracranial hemorrhage.

Relevance Proof of Safety Culture in Coal Mine Industry.

This paper intends to use data to verify the correlation between safety culture, safety management system and safety knowledge, safety awareness, and safety habits, which is the correlation between the various parts of the behavior safety "2-4" model. Due to data limitations, the results are limited to the study of safety culture related relationships in coal mining enterprises. This paper first designed a questionnaire containing 30 questions, of which 1⁻5 questions represent safety culture, 6⁻22 questions represent safety management system, and 23⁻30 questions represent safety knowledge, safety awareness and safety habits. Employees of 27 coal mining enterprises in Shandong, Henan, Hunan and other places in China were surveyed and sampled by stratified random sampling, and 1514 valid questionnaires were obtained. After item analysis and correlation analysis, and it was found that, within the data of 1514 questionnaires, the item total correlation coefficients of questions 6, 9, 19 and 28 were all less than 0.2, indicating that the identification degree of these four items was poor, which was deleted. Using the data analysis of the remaining 26 questions in the questionnaire, it was found that the relationship between safety culture and the safety management system, the safety management system and safety knowledge, and safety awareness and safety habits is moderately related; safety culture and safety knowledge, safety awareness and safety habits are weakly related. The conclusion shows that the safety culture directly affects the safety management system; the safety management system directly affects the safety knowledge, safety awareness and safety habits; the safety culture indirectly affects safety knowledge, safety awareness and safety habits. However, why the expected strong correlation is not achieved, and whether the same conclusion can be obtained if the data scale is expanded or other types of enterprises are added for questionnaire measurement, these are questions worthy of further study, which is also the author's next research content.

Chinese Military Evaluation of a Portable Near-Infrared Detector of Traumatic Intracranial Hematomas.

Introduction: Secondary brain injury is the main cause of mortality from traumatic brain injury (TBI). One hallmark of TBI is intracranial hemorrhage, which occurs in 40-50% of severe TBI cases. Early identification of intracranial hematomas in TBI patients allows early surgical evacuation and can reduce the case fatality rate of TBI. As pre-hospital care is the weakest part of Chinese emergency care, there is an urgent need for a capability to detect brain hematomas early. In China, in addition to preventing injuries and diseases in military staff and in enhancing the military armed forces during war, military medicine participates in actions such as emergency public health crises, natural disasters, emerging conflicts, and anti-terrorist campaigns during peacetime. The purpose of this observational study is to evaluate in the Chinese military general hospital the performance of a near-infrared (NIR)-based portable device, developed for US Military, in the detection of traumatic intracranial hematomas. The endpoint of the study was a description of the test characteristics (sensitivity, specificity, and positive and negative predictive values [NPV]) of the portable NIR-based device in identification of hematomas within its detection limits (volume >3.5 mL and depth <2.5 cm) compared with computed tomography (CT) scans as the gold standard. Materials and Methods: The Infrascanner Model 2000 NIR device (InfraScan, Inc., Philadelphia, PA, USA) was used for hematoma detection in patients sustaining TBI. Data were collected in the People's Liberation Army General Hospital in Beijing using the NIR device at the time of CT scans, which were performed to evaluate suspected TBI. One hundred and twenty seven patients were screened, and 102 patients were included in the per protocol population. Of the 102 patients, 24 were determined by CT scan to have intracranial hemorrhage. The CT scans were read by an independent neuroradiologist who was blinded to the NIR measurements. Results: The NIR device demonstrated sensitivity of 100% (95% confidence intervals [CI] 82.8-100%) and specificity of 93.6% (95%CI 85-97.6%) in detecting intracranial hematomas larger than 3.5 mL in volume and that were less than 2.5 cm from the surface of the brain. Blood contained within scalp hematomas was found to be a major cause of false-positive results with this technology. Conclusion: The study showed that the Infrascanner is a suitable portable device in Chinese population for detecting preoperative intracranial hematomas in remote locations, emergency rooms, and intensive care units. It could aid military medics, physicians, and hospital staff, permitting better triage decisions, earlier treatment, and reducing secondary brain injury caused by acute and delayed hematomas.

beta-TrCP binding and processing of NF-kappaB2/p100 involve its phosphorylation at serines 866 and 870.

Processing of the NF-kappaB2 precursor protein p100 is a major step in noncanonical NF-kappaB signaling. This signaling step requires the NF-kappaB inducing kinase (NIK) and its downstream kinase, IkappaB kinase alpha (IKKalpha). We show here that p100 undergoes phosphorylation at serines 866, 870, and possibly 872, in cells stimulated with noncanonical NF-kappaB stimuli or transfected with NIK and IKKalpha. Phosphorylation of this serine cluster creates a binding site for beta-TrCP, the receptor subunit of the beta-TrCP(SCF) ubiquitin ligase. Mutation of either serine 866 or serine 870 abolishes the beta-TrCP recruitment and ubiquitination of p100. The functional significance of p100 phosphorylation is further supported by the finding that this molecular event occurs in a NIK- and IKKalpha-dependent manner. Additionally, induction of p100 phosphorylation can be blocked by a protein synthesis inhibitor, suggesting the requirement of de novo protein synthesis. These data suggest that p100 processing involves its phosphorylation at specific terminal serines, which form a binding site for beta-TrCP thereby regulating p100 ubiquitination.

[Expression of c-myc mRNA on early restenosis after carotid endarterectomy].

OBJECTIVE: To explore the expression and changes of protooncogene c-myc in early restenosis after carotid endarterectomy (CEA). METHODS: Using New Zealand Rabbits, carotid atherosclerotic stenosis (CASS) model were created. The expression of c-myc in early restenosis after CEA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: In this experiment protooncogene c-myc was analysed at pre-operation, 4 hours and 1 d after CEA by qRT-PCR, and the level of mRNA of c-myc was reached maximum at 4 hours, and decreased following significantly, but still higher than pre-operation. CONCLUSIONS: The activation of protooncogene c-myc may be generator factor of vascular smooth muscle cell proliferation.

The effects of pharmaceutical thrombolysis and multi-modal therapy on patients with acute posterior circulation ischemic stroke: Results of a one center retrospective study.

BACKGROUND: The treatment method for acute ischemic stroke is rapidly developing, and the effects of endovascular modalities, when used alone or in combination, needs to be studied. We aimed to identify the difference between pharmaceutical thrombolysis and multi-modal therapy (MMT) used in acute posterior circulation ischemic stroke (APCIS) patients and also to detect the predictors for successful recanalization and favorable outcomes. METHODS: A retrospective analysis of patients with APCIS who received thrombolytic pharmaceuticals and MMT from 2011 to 2016 was performed at the stroke center. Demographic information, therapeutic methods and the results were recorded. Logistic regression model was constructed in variables to determine the predictors of outcome. RESULTS: A total of 124 patients were included in this study, the mean age was 59.6 ± 9.5 years and the mean admission National Institutes of Health Stroke Scale (NIHSS) was 15.1 ± 6.6. Recanalization was achieved in 87 (70.2%) patients and favorable outcomes were observed in 65 (52.4%) patients. Patients treated with MMT demonstrated a higher recanalization rate, especially the use of stent placement and thrombectomy device, which were also related to the favorable outcome three months post-stroke. Logistic regression showed that stent placement and thrombectomy were the predictors of recanalization, and a favorable outcome was associated with coronary artery disease, MMT methods as well as recanalization. CONCLUSION: MMT methods, especially stent placement and thrombectomy device may be the first recommended for patients with a delayed admission time, and it may have the advantage of better perfusion and neurological outcomes.

CBCT-based 3D MRA and angiographic image fusion and MRA image navigation for neuro interventions.

Digital subtracted angiography (DSA) remains the gold standard for diagnosis of cerebral vascular diseases and provides intraprocedural guidance. This practice involves extensive usage of x-ray and iodinated contrast medium, which can induce side effects. In this study, we examined the accuracy of 3-dimensional (3D) registration of magnetic resonance angiography (MRA) and DSA imaging for cerebral vessels, and tested the feasibility of using preprocedural MRA for real-time guidance during endovascular procedures.Twenty-three patients with suspected intracranial arterial lesions were enrolled. The contrast medium-enhanced 3D DSA of target vessels were acquired in 19 patients during endovascular procedures, and the images were registered with preprocedural MRA for fusion accuracy evaluation. Low-dose noncontrasted 3D angiography of the skull was performed in the other 4 patients, and registered with the MRA. The MRA was overlaid afterwards with 2D live fluoroscopy to guide endovascular procedures.The 3D registration of the MRA and angiography demonstrated a high accuracy for vessel lesion visualization in all 19 patients examined. Moreover, MRA of the intracranial vessels, registered to the noncontrasted 3D angiography in the 4 patients, provided real-time 3D roadmap to successfully guide the endovascular procedures. Radiation dose to patients and contrast medium usage were shown to be significantly reduced.Three-dimensional MRA and angiography fusion can accurately generate cerebral vasculature images to guide endovascular procedures. The use of the fusion technology could enhance clinical workflow while minimizing contrast medium usage and radiation dose, and hence lowering procedure risks and increasing treatment safety.

Analysis of prognostic factors of endovascular therapy in 59 patients with acute anterior circulation stroke: a retrospective cohort study ­ observational.

INTRODUCTION: Endovascular therapy (ET) is increasingly used for stroke patients out of the time window, based on the multimodal treatment (MMT) it can be used alone or in combination. The purpose of this study was to assess the outcome of intra-arterial thrombolysis (IAT) and MMT for acute anterior circulation ischemic stroke (ACIS), and reveal prognostic factors of ET in the authors' stroke center. METHODS: A retrospective analysis of the data of 59 patients with ACIS who received ET from 2010 to 2014 in the stroke center was performed. A univariate analysis was conducted to reveal the differences between IAT and MMT, and the distinctions between favorable and unfavorable outcomes, logistic regression analysis was performed to determine the predictors of outcomes. RESULTS: Thirty-four patients who accepted MMT had a higher baseline National Institutes of Health Stroke Scale score on admission (18.3 ± 4.2) compared with 25 patients who were treated with IAT (12.6 ± 4.3). The MMT group had a higher patent flow (23/34) (thrombolysis in myocardial infarction grade 2-3) compared with the IAT group (10/25). Moreover, the MMT group had a longer time for emergency department (ED) (5.8 ± 1.4) than the IAT group (5.2 ± 0.8). In multivariate analysis, age, time to ED, and NIHSS score at discharge are predictors for poor outcome, whereas perfect recanalization was associated with favorable outcome. CONCLUSION: MMT might be suitable for patients with a severe admission NIHSS and a higher patency rate than IAT. Vessel recanalization was the only predictor for favorable outcome.

[Fertility alteration of male sterile rice line annong S-1 and the expression of fertility related aprt gene].

The thermo-sensitive point and the thermo-sensitive stage for fertility alteration in the thermo-sensitive genic male sterile (TGMS) line Annong S-1 were studied. In nature environment and green house,the leaf, root and young panicle were treated by low and high temperature respectively. In total, 8 treatments were carried out. Results indicated that during the thermo-sensitive stage of fertility alteration, in high temperature environmental conditions, the low temperature treatment in the root did not significantly induce Annong S-1 to be fertile, while the low temperature treatment in young panicle obviously induced Annong S-1 to be fertile. Therefore, the thermo-sensitive point of Annong S-1 is the young panicle. The stage of fertility alteration was also investigated. Results indicated that alteration occurred in the phase from the formation of pollen mother cell to the tetrad of miosis. aprt gene is related the male sterility. The expression of aprt gene in root,young panicle and leaf were investigated by RT-PCR respectively. In young panicle, the expression of aprt gene was greatly down regulated by high temperature, while in root and leaf the expressions have no great changes. These data show that the young panicle is sensitive to temperature change. The result also supported that the young panicle is the thermo-sensitive point of Annong S-1 in the fertility alteration. These conclusions can be used to direct in hybrid rice seed production.

[Genetic mapping of resistant gene to southern corn rust and the tagging analysis on different genetic background].

Southern corn rust (SCR) is a destructive disease in maize. The inbred line Qi319 is highly resistant to southern corn rust. SSR technique was employed to preliminary mapping of the resistance gene. Bulked segregant analysis revealed that two primers, phi 118 and phi 041, amplified polymorphic bands. SSR analysis on populations indicated the two primers were linked to the rust resistance gene, which was mapped on the short arm of chromosome 10. In addition, comparative analysis of the amplification bands among different populations revealed that the amplification products with the same primer in different populations were dissimilar. This result indicates that the genetic background may affect results of gene mapping and tagging. So, it is important to select suitable population to performing molecular marker analysis and gene mapping.

The translin-TRAX complex (C3PO) is a ribonuclease in tRNA processing.

Conserved translin-TRAX complexes, also known as C3POs, have been implicated in many biological processes, but how they function remains unclear. Recently, C3PO was shown to be an endoRNase that promotes RNA interference (RNAi) in animal cells. Here, we show that C3PO does not play a significant role in RNAi in the filamentous fungus Neurospora crassa. Instead, the Neurospora C3PO functions as an RNase that removes the 5' pre-tRNA fragments after the processing of pre-tRNAs by RNase P. In addition, translin and trax mutants have elevated levels of tRNA and protein translation and are more resistant to a cell death-inducing agent. Finally, we show that C3PO is also involved in tRNA processing in mouse embryonic fibroblast cells. This study identifies the endogenous RNA substrates of C3PO and provides a potential explanation for its roles in apparently diverse biological processes.

C3PO, an endoribonuclease that promotes RNAi by facilitating RISC activation.

The catalytic engine of RNA interference (RNAi) is the RNA-induced silencing complex (RISC), wherein the endoribonuclease Argonaute and single-stranded small interfering RNA (siRNA) direct target mRNA cleavage. We reconstituted long double-stranded RNA- and duplex siRNA-initiated RISC activities with the use of recombinant Drosophila Dicer-2, R2D2, and Ago2 proteins. We used this core reconstitution system to purify an RNAi regulator that we term C3PO (component 3 promoter of RISC), a complex of Translin and Trax. C3PO is a Mg2+-dependent endoribonuclease that promotes RISC activation by removing siRNA passenger strand cleavage products. These studies establish an in vitro RNAi reconstitution system and identify C3PO as a key activator of the core RNAi machinery.