Methodological Quality of Pulmonary Arterial Hypertension Treatment Evidence-Based Guidelines: A Systematic Review Using the AGREE II and AGREE REX Tools.

PURPOSE: Pulmonary arterial hypertension (PAH) is a progressive disease with a poor prognosis, and its management should be grounded in well-developed clinical practice guidelines (CPG). Thus, we critically assess the methodological quality of the available CPG for pharmacological treatments for PAH. METHODS: A systematic review (CRD42023387168) was performed in PubMed, Cochrane, Embase, and Tripdatabase (Jan-2023). Eligible records were appraised by four reviewers using the Appraisal of Guidelines, Research, and Evaluation Collaboration tool (AGREE II) and the complementary tool for assessing recommendations' quality and certainty, AGREE REX. Descriptive statistics were used to summarize the data. RESULTS: Overall, 31 guidelines, mainly authored by professional societies (90%), targeting only physicians as primary users (84%), were identified. Guidelines presented a moderate overall quality (scores of 63% and 51% in AGREE II and AGREE REX, respectively), with a few domains showing slight improvements over the years. AGREE II "Scope and Purpose" (94%) and "Presentation Clarity" (99%) domains obtained the highest scores. The items related to "Stakeholder involvement," "Editorial independence," and "Clinical applicability" (AGREE REX) were fairly reported. Conversely, CPG lacks rigor in development (32% score, AGREE II), scarcely discusses the role of stakeholders, and provides deficient data on the implementation of recommendations (scores of 35% and 46% in AGREE II and AGREE REX, respectively). No differences in the quality of guidelines published by different developers or countries were observed (p > 0.05). CONCLUSION: Methodological weaknesses are common among guidelines addressing PAH treatment, especially regarding scientific rigor, stakeholders' values and preferences, and facilitators and barriers to implementability. Particular attention should be given to developing future guidelines.

Interlude 1: Crablike Collective Moves.

This interlude follows the AAH conference, when all of the authors who contribute to the special journal edition are present. Their wide-ranging conversation covers the idea and possibilities of a polyphonic history of art. This interlude is a starting point, a jumping off point from where a group of authors, researchers and artists reflect on new ways of thinking about, and new ways of presenting, art history. Their conversation develops an ambition to move away from the well-trodden and often reductive methodological frameworks of art history, as they debate ideas around transnationalism, globalism, artist-centric art histories and the idea of artist as author. This interlude is about collective endeavours, both by the subjects being discussed in each paper, and by the authors who are writing about them.

Silicone rubber membrane devices permit islet culture at high density without adverse effects.

Introduction: Conventional culture conditions, such as in T-flasks, require that oxygen diffuse through the medium to reach the islets; in turn, islet surface area density is limited by oxygen availability. To culture a typical clinical islet preparation may require more than 20 T-175 flasks at the standard surface area density of 200 IE/cm2. To circumvent this logistical constraint, we tested islets cultured on top of silicon gas-permeable (GP) membranes which place islets in close proximity to ambient oxygen. Methods: Oxygenation of individual islets under three culture conditions, standard low-density, non-GP high density, and GP high density, were first modeled with finite element simulations. Porcine islets from 30 preparations were cultured for 2 days in devices with GP membrane bottoms or in paired cultures under conventional conditions. Islets were seeded at high density (HD, ∼4000 IE/cm2, as measured by DNA) in both GP and non-GP devices. Results: In simulations, individual islets under standard culture conditions and high density cultures on GP membranes were both well oxygenated whereas non-GP high density cultured islets were anoxic. Similarly, compared to the non-GP paired controls, islet viability and recovery were significantly increased in HD GP cultures. The diabetes reversal rate in nude diabetic mice was similar for HD GP devices and standard cultures but was minimal with non-GP HD cultures. Discussion: Culturing islets in GP devices allows for a 20-fold increase of islet surface area density, greatly simplifying the culture process while maintaining islet viability and metabolism.

Propensity score matching for comparative studies: a tutorial with R and Rex.

Recently, there has been considerable progress in developing new technologies and equipment for the medical field, including minimally invasive surgeries. Evaluating the effectiveness of these treatments requires study designs like randomized controlled trials. However, due to the nature of certain treatments, randomization is not always feasible, leading to the use of observational studies. The effect size estimated from observational studies is subject to selection bias caused by confounders. One method to reduce this bias is propensity scoring. This study aimed to introduce a propensity score matching process between two groups using a practical example with R. Additionally, Rex, an Excel add-in graphical user interface statistical program, is provided for researchers unfamiliar with R programming. Further techniques, such as matching with three or more groups, propensity score weighting and stratification, and imputation of missing values, are summarized to offer approaches for more complex studies not covered in this tutorial.

Migration, invasion, and metastasis are mediated by P-Rex1 in neuroblastoma.

Neuroblastoma accounts for approximately 15% of pediatric cancer-related deaths despite intensive multimodal therapy. This is due, in part, to high rates of metastatic disease at diagnosis and disease relapse. A better understanding of tumor biology of aggressive, pro-metastatic phenotypes is necessary to develop novel, more effective therapeutics against neuroblastoma. Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1 (P-Rex1) has been found to stimulate migration, invasion, and metastasis in several adult malignancies. However, its role in neuroblastoma is currently unknown. In the present study, we found that P-Rex1 is upregulated in pro-metastatic murine models of neuroblastoma, as well as human neuroblastoma metastases. Correspondingly, silencing of P-Rex1 was associated with decreased migration and invasion in vitro. This was associated with decreased AKT-mTOR and ERK2 activity, dysregulation of Rac, and diminished secretion of matrix metalloproteinases. Furthermore, increased P-Rex1 expression was associated with inferior relapse-free and overall survival via tissue microarray and Kaplan-Meier survival analysis of a publicly available clinical database. Together, these findings suggest that P-Rex1 may be a novel therapeutic target and potential prognostic factor in neuroblastoma.

Exploratory Research for New Diagnostic Markers of Mucormycosis.

Mucormycosis is a fungal infectious disease caused by Rhizopus oryzae and other members of the order Mucorales, and it is known as one of the most lethal fungal infections. Early diagnosis of mucormycosis improves prognosis because of limited effective treatments and the rapid progression of the disease. On the other hand, the lack of characteristic clinical findings in mucormycosis and the challenge of early definitive diagnosis make early treatment difficult. Our goal was to establish a serodiagnostic method to detect Rhizopus specific antigen (RSA), and we have developed a diagnostic kit by Enzyme-linked immuno-sorbent assay (ELISA) using a monoclonal antibody against this antigen. RSA increased over time in the serum and alveolar lavage fluid of R. oryzae-infected mice. RSA was also detected in serum and alveolar fluid, even at an early stage (Day 1), when the tissue invasion of R. oryzae mycelium was not histopathologically detectable in the lungs of R. oryzae-infected mice. Further evaluation is needed to determine the feasibility of using this assay in clinical practice.

Wedged hepatic vein portovenography for assessment of Rex vein patency in children with extrahepatic portal venous obstruction.

BACKGROUND: Meso-Rex bypass is the surgical intervention of choice for children with extrahepatic portal vein obstruction (EHPVO). Patency of Rex vein, umbilical recessus of the portal vein, is a prerequisite for this surgery. Conventional diagnostic modalities poorly detect patency, while transjugular wedged hepatic vein portography (WHVP) accurately detects patency in 90%. OBJECTIVES: We aimed to assess Rex vein patency and portal vein branching pattern in children with EHPVO using transjugular WHVP and to identify factors associated with Rex vein patency. METHODS: Transjugular WHVP was performed in 31 children with EHPVO by selective cannulation of left and right hepatic veins. Rex vein patency, type of intrahepatic portal venous anatomy (Types A-E), and factors associated with patency of Rex vein were studied. RESULTS: The patency of Rex recess on transjugular WHVP was 29%. Complete obliteration of intrahepatic portal venous radicles was the commonest pattern (Type E, 38.7%) while Type A, the favorable anatomy for meso-Rex bypass, was seen in only 12.9%. Patency of the Rex vein, but not the anatomical pattern, was associated with younger age at evaluation (patent Rex: 6.6 ± 4.9 years vs. nonpatent Rex: 12.7 ± 3.9 years, p = 0.001). Under-5-year children had a 12 times greater chance of having a patent Rex vein (odds ratio: 12.22, 95% confidence interval: 1.65-90.40, p = 0.004). Patency or pattern was unrelated to local factors like umbilical vein catheterization, systemic thrombophilia, or disease severity. CONCLUSION: Less than one-third of our pediatric EHPVO patients have a patent Rex vein. Younger age at evaluation is significantly associated with Rex vein patency.

Rotary excitation of non-sinusoidal pulsed magnetic fields: Towards non-invasive direct detection of cardiac conduction.

PURPOSE: There is a need for high resolution non-invasive imaging methods of physiologic magnetic fields. The purpose of this work is to develop a MRI detection approach for non-sinusoidal magnetic fields based on the rotary excitation (REX) mechanism which was previously successfully applied for the detection of oscillating magnetic fields in the sub-nT range. METHODS: The new detection concept was examined by means of Bloch simulations, evaluating the interaction effect of spin-locked magnetization and low-frequency pulsed magnetic fields. The REX detection approach was validated under controlled conditions in phantom experiments at 3 T. Gaussian and sinc-shaped stimuli were investigated. In addition, the detection of artificial fields resembling a cardiac QRS complex, which is the most prominent peak visible on a magnetocardiogram, was tested. RESULTS: Bloch simulations demonstrated that the REX method has a high sensitivity to pulsed fields in the resonance case, which is met when the spin-lock frequency coincides with a non-zero Fourier component of the stimulus field. In the experiments, we found that magnetic stimuli of different durations and waveforms can be distinguished by their characteristic REX response spectrum. The detected REX amplitude was proportional to the stimulus peak amplitude (R2 > 0.98) and the lowest field detection was 1 nT. Furthermore, the detection of QRS-like fields with varying QRS durations yielded significant results in a phantom setup (p < 0.001). CONCLUSION: REX detection can be transferred to non-sinusoidal pulsed magnetic fields and could provide a non-invasive, quantitative tool for spatially resolved assessment of cardiac biomagnetism. Potential applications include the direct detection and characterization of cardiac conduction.

Betaglycan sustains HGF/Met signaling in lung cancer and endothelial cells promoting cell migration and tumor growth.

Persistent HGF/Met signaling drives tumor growth and dissemination. Proteoglycans within the tumor microenvironment might control HGF availability and signaling by affecting its accessibility to Met (HGF receptor), likely defining whether acute or sustained HGF/Met signaling cues take place. Given that betaglycan (BG, also known as type III TGFß receptor or TGFBR3), a multi-faceted proteoglycan TGFß co-receptor, can be found within the tumor microenvironment, we addressed its hypothetical role in oncogenic HGF signaling. We found that HGF/Met promotes lung cancer and endothelial cells migration via PI3K and mTOR. This effect was enhanced by recombinant soluble betaglycan (solBG) via a mechanism attributable to its glycosaminoglycan chains, as a mutant without them did not modulate HGF effects. Moreover, soluble betaglycan extended the effect of HGF-induced phosphorylation of Met, Akt, and Erk, and membrane recruitment of the RhoGEF P-Rex1. Data-mining analysis of lung cancer patient datasets revealed a significant correlation between high MET receptor, HGF, and PREX1 expression and reduced patient survival. Soluble betaglycan showed biochemical interaction with HGF and, together, they increased tumor growth in immunocompetent mice. In conclusion, the oncogenic properties of the HGF/Met pathway are enhanced and sustained by GAG-containing soluble betaglycan.

How does the Xist activator Rlim/Rnf12 regulate Xist expression?

The long non-coding RNA (lncRNA) Xist is crucially involved in a process called X chromosome inactivation (XCI), the transcriptional silencing of one of the two X chromosomes in female mammals to achieve X dosage compensation between the sexes. Because Xist RNA silences the X chromosome from which it is transcribed, the activation of Xist transcription marks the initiation of the XCI process and thus, mechanisms and players that activate this gene are of central importance to the XCI process. During female mouse embryogenesis, XCI occurs in two steps. At the 2-4 cell stages imprinted XCI (iXCI) silences exclusively the paternally inherited X chromosome (Xp). While extraembryonic cells including trophoblasts keep the Xp silenced, epiblast cells that give rise to the embryo proper reactivate the Xp and undergo random XCI (rXCI) around implantation. Both iXCI and rXCI are dependent on Xist. Rlim, also known as Rnf12, is an X-linked E3 ubiquitin ligase that is involved in the transcriptional activation of Xist. However, while data on the crucial involvement of Rlim during iXCI appear clear, its role in rXCI has been controversial. This review discusses data leading to this disagreement and recent evidence for a regulatory switch of Xist transcription in epiblasts of implanting embryos, partially reconciling the roles of Rlim during Xist activation.

How consistent are the key recommendations, and what is the quality of guidelines and expert consensus regarding paediatric cow's milk protein allergy?

The objective of this study was to assess the quality and consistency of recommendations in clinical practice guidelines (CPGs) and expert consensus on paediatric cow's milk protein allergy (CMPA) to serve as a foundation for future revisions and enhancements of clinical guidelines and consensus documents. We conducted a comprehensive literature search across several databases, including the Chinese Biomedical Literature Database (CBM), PubMed, Embase, Web of Science, UpToDate, ClinicalKey, DynaMed Plus and BMJ Best Practice. We spanned the search period from the inception of each database through October 1, 2023. We integrated subject headings (MeSH/Emtree) and keywords into the search strategy, used the search methodologies of existing literature and developed it in collaboration with a librarian. Two trained researchers independently conducted the literature screening and data extraction. We evaluated methodological quality and recommendations by using the Appraisal of Guidelines for Research & Evaluation II (AGREE II) and AGREE-Recommendations for Excellence (AGREE-REX) tools. Moreover, we compared and summarized key recommendations from high-quality CPGs. Our study included 27 CPGs and expert consensus documents on CMPA. Only four CPGs (14.8%) achieved a high-quality AGREE II rating. The four high-quality CPGs consistently provided recommendations for CMPA. The highest scoring domains for AGREE II were 'scope and purpose' (77 ± 12%) and 'clarity of presentation' (75 ± 22%). The lowest scoring domains were 'stakeholder involvement' (49 ± 21%), 'rigor of development' (34 ± 20%) and 'applicability' (12 ± 20%). Evaluation with AGREE-REX generally demonstrated low scores across its domains.   Conclusion: Recommendations within high-quality CPGs for the paediatric CMPA showed fundamental consistency. Nevertheless, the methodology and recommendation content of CPGs and the expert consensus exhibited low quality, thus indicating a substantial scope for enhancement. Guideline developers should rigorously follow the AGREE II and AGREE-REX standards in creating CPGs or expert consensuses to guarantee their clinical efficacy in managing paediatric CMPA. What is Known: • The quality of clinical practice guidelines and expert consensus on paediatric cow's milk protein allergy (CMPA) remains uncertain. • There is a lack of clarity regarding the consistency of crucial recommendations for CMPA management. What is New: • Improving the methodological quality of guidelines and consensus on CMPA requires greater emphasis on stakeholder engagement, rigorous development processes, and practical applicability. • The recommendations from four high-quality guidelines align. However, addressing clinical applicability, integrating values and preferences, and ensuring actionable implementation are critical to improving the quality of all guidelines.

Elevator music as a tool for the quantitative characterization of reward.

While certain musical genres and songs are widely popular, there is still large variability in the music that individuals find rewarding or emotional, even among those with a similar musical enculturation. Interestingly, there is one Western genre that is intended to attract minimal attention and evoke a mild emotional response: elevator music. In a series of behavioral experiments, we show that elevator music consistently elicits low pleasure and surprise. Participants reported elevator music as being less pleasurable than music from popular genres, even when participants did not regularly listen to the comparison genre. Participants reported elevator music to be familiar even when they had not explicitly heard the presented song before. Computational and behavioral measures of surprisal showed that elevator music was less surprising, and thus more predictable, than other well-known genres. Elevator music covers of popular songs were rated as less pleasurable, surprising, and arousing than their original counterparts. Finally, we used elevator music as a control for self-selected rewarding songs in a proof-of-concept physiological (electrodermal activity and piloerection) experiment. Our results suggest that elevator music elicits low emotional responses consistently across Western music listeners, making it a unique control stimulus for studying musical novelty, pleasure, and surprise.

Chromosome-scale genomes of Quercus sichourensis and Quercus rex provide insights into the evolution and adaptation of Fagaceae.

The Fagaceae, a plant family with a wide distribution and diverse adaptability, has garnered significant interest as a subject of study in plant speciation and adaptation. Meanwhile, certain Fagaceae species are regarded as highly valuable wood resources due to the exceptional quality of their wood. In this study, we present two high-quality, chromosome-scale genome sequences for Quercus sichourensis (848.75 Mb) and Quercus rex (883.46 Mb). Comparative genomics analysis reveals that the difference in the number of plant disease resistance genes and the nonsynonymous and synonymous substitution ratio (Ka/Ks) of protein-coding genes among Fagaceae species are related to different environmental adaptations. Interestingly, most genes related to starch synthesis in the investigated Quercoideae species are located on a single chromosome, as compared to the outgroup species, Fagus sylvatica. Furthermore, resequencing and population analysis of Q. sichourensis and Q. rex reveal that Q. sichourensis has lower genetic diversity and higher deleterious mutations compared to Q. rex. The high-quality, chromosome-level genomes and the population genomic analysis of the critically endangered Q. sichourensis and Q. rex will provide an invaluable resource as well as insights for future study in these two species, even the genus Quercus, to facilitate their conservation.

Heterochromatin repeat organization at an individual level: Rex1BD and the 14-3-3 protein coordinate to shape the epigenetic landscape within heterochromatin repeats.

In eukaryotic cells, heterochromatin is typically composed of tandem DNA repeats and plays crucial roles in gene expression and genome stability. It has been reported that silencing at individual units within tandem heterochromatin repeats exhibits a position-dependent variation. However, how the heterochromatin is organized at an individual repeat level remains poorly understood. Using a novel genetic approach, our recent study identified a conserved protein Rex1BD required for position-dependent silencing within heterochromatin repeats. We further revealed that Rex1BD interacts with the 14-3-3 protein to regulate heterochromatin silencing by linking RNAi and HDAC pathways. In this review, we discuss how Rex1BD and the 14-3-3 protein coordinate to modulate heterochromatin organization at the individual repeat level, and comment on the biological significance of the position-dependent effect in heterochromatin repeats. We also identify the knowledge gaps that still need to be unveiled in the field.

Climbing into their Skin to Understand Contextual Protein-Protein Associations and Localizations: Functional Investigations in Transgenic Live Model Organisms.

Borrowing some quotes from Harper Lee's novel "To Kill A Mockingbird" to help frame our manuscript, we discuss methods to profile local proteomes. We initially focus on chemical biology regimens that function in live organisms and use reactive biotin species for this purpose. We then consider ways to add new dimensions to these experimental regimens, principally by releasing less reactive (i. e., more selective) (preter)natural electrophiles. Although electrophile release methods may have lower resolution and label fewer proteins than biotinylation methods, their ability to probe simultaneously protein function and locale raises new and interesting possibilities for the field.

Selection Signatures Reveal Candidate Genes for the Cornish Rex Breed-Specific Phenotype.

Many coat color, behavioral and morphological traits are specific and fixed across cat breeds, with several variants influencing these traits being common among different breeds. In the domestic cat, rexoid mutations have been documented in several breeds. In the Cornish Rex, four bp deletion in the LPAR6 gene has been found to cause a frame shift and a premature stop codon. In addition to the rexoid coat, Cornish Rex cats also have a characteristic head, ear shape and body type. Analysis of the selection signatures in the Cornish Rex genome revealed several regions that are under selective pressure. One of these is located in CFA B4, in the region where the ALX1 gene is located. The ALX1 gene in Burmese cats disrupts the cranial morphogenesis and causes brachycephaly in the heterozygous state. In our study, we confirmed the presence of a deletion in LPAR6 in 20 Cornish Rex and in four F1 hybrids between Cornish Rex and domestic cat. However, we did not confirm the presence of the deletion in ALX1 in Cornish Rex cats. Genome-wide selection signature analysis was performed using ROH islands and integrated haplotype score (iHS) statistics based on publicly available SNP array data of 11 Cornish Rex cats. The selection signatures were detected on chromosomes A1, A3, C2, B1, B4 and D1.

Effectiveness of anticoagulant therapy using heparin combined with Plavix after Rex shunt.

Purpose: Rex shunt is an optimal surgery for the treatment of extra-hepatic portal venous obstruction (EHPVO) in children. Anticoagulant therapy has been used to keep the patency of the bypass vein in the Rex shunt. This study was to investigate the effectiveness of anticoagulant therapy using heparin combined with Plavix in improving the prognosis and shunt patency of Rex shunt. Methods: From January 2010 to September 2019, 51 children with EHPVO underwent a portal cavernoma- Rex shunt. Based on whether using the anticoagulant therapy after the Rex shunt, all patients were divided into two groups: the anticoagulant group and the non-anticoagulant group. The diameter and flow velocity of the bypass vein were measured by the post-operative ultrasound, which was used to calculate the flow volume of the bypass vein (FV) and standard portal venous flow (SPVF). The bypass venous flow index (BVFI) was used to evaluate the ability of portal blood into the liver through the bypass vein after the Rex shunt, which was a ratio of FV to SPVF. The incidence of post-operative re-bleeding, the postoperative patency rate of the bypass vein, the remission rate of postoperative hypersplenism, the remission rate of postoperative esophagogastric varices and the BVFI were compared between the two groups. Results: Of the 51 patients, 12 patients in the anticoagulant group were treated with heparin combined with Plavix after Rex shunt; 39 patients in the non-anticoagulant group were not treated with any anticoagulant therapy. 8 of 51 patients suffered from postoperative re-bleeding, of whom 6 patients with thrombosis of the bypass vein and 2 patients with anastomotic stenosis of the bypass vein. All 8 patients with re-bleeding belonged to the non-anticoagulant group. The remission rate of hypersplenism was no significant difference between the two groups after surgery (91% vs. 58%, P = 0.100). However, 3 patients without hypersplenism before surgery suffered from hypersplenism after surgery, who belonged to the non-anticoagulant group. There was no significant difference in the remission rate of esophagogastric varices (33% vs. 46%, P = 1.000). The BVFI of the anticoagulant group was significantly higher than that of the non-anticoagulant group (5.71 ± 5.89 vs. 1.1 ± 1.52, P = 0.003). Conclusions: Anticoagulant therapy using heparin combined with Plavix plays an important role in maintaining the patency of the bypass vein, which improved the portal blood flow into the liver through the bypass vein after the Rex shunt.

Rex1BD and the 14-3-3 protein control heterochromatin organization at tandem repeats by linking RNAi and HDAC.

Tandem DNA repeats are often organized into heterochromatin that is crucial for genome organization and stability. Recent studies revealed that individual repeats within tandem DNA repeats can behave very differently. How DNA repeats are assembled into distinct heterochromatin structures remains poorly understood. Here, we developed a genome-wide genetic screen using a reporter gene at different units in a repeat array. This screen led to identification of a conserved protein Rex1BD required for heterochromatin silencing. Our structural analysis revealed that Rex1BD forms a four-helix bundle structure with a distinct charged electrostatic surface. Mechanistically, Rex1BD facilitates the recruitment of Clr6 histone deacetylase (HDAC) by interacting with histones. Interestingly, Rex1BD also interacts with the 14-3-3 protein Rad25, which is responsible for recruiting the RITS (RNA-induced transcriptional silencing) complex to DNA repeats. Our results suggest that coordinated action of Rex1BD and Rad25 mediates formation of distinct heterochromatin structure at DNA repeats via linking RNAi and HDAC pathways.

Roles of the Rlim-Rex1 axis during X chromosome inactivation in mice.

In female mice, the gene dosage from X chromosomes is adjusted by a process called X chromosome inactivation (XCI) that occurs in two steps. An imprinted form of XCI (iXCI) that silences the paternally inherited X chromosome (Xp) is initiated at the 2- to 4-cell stages. As extraembryonic cells including trophoblasts keep the Xp silenced, epiblast cells that give rise to the embryo proper reactivate the Xp and undergo a random form of XCI (rXCI) around implantation. Both iXCI and rXCI require the lncRNA Xist, which is expressed from the X to be inactivated. The X-linked E3 ubiquitin ligase Rlim (Rnf12) in conjunction with its target protein Rex1 (Zfp42), a critical repressor of Xist, have emerged as major regulators of iXCI. However, their roles in rXCI remain controversial. Investigating early mouse development, we show that the Rlim-Rex1 axis is active in pre-implantation embryos. Upon implantation Rex1 levels are downregulated independently of Rlim specifically in epiblast cells. These results provide a conceptual framework of how the functional dynamics between Rlim and Rex1 ensures regulation of iXCI but not rXCI in female mice.

Retroviral hijacking of host transport pathways for genome nuclear export.

Recent advances in the study of virus-cell interactions have improved our understanding of how viruses that replicate their genomes in the nucleus (e.g., retroviruses, hepadnaviruses, herpesviruses, and a subset of RNA viruses) hijack cellular pathways to export these genomes to the cytoplasm where they access virion egress pathways. These findings shed light on novel aspects of viral life cycles relevant to the development of new antiviral strategies and can yield new tractable, virus-based tools for exposing additional secrets of the cell. The goal of this review is to summarize defined and emerging modes of virus-host interactions that drive the transit of viral genomes out of the nucleus across the nuclear envelope barrier, with an emphasis on retroviruses that are most extensively studied. In this context, we prioritize discussion of recent progress in understanding the trafficking and function of the human immunodeficiency virus type 1 Rev protein, exemplifying a relatively refined example of stepwise, cooperativity-driven viral subversion of multi-subunit host transport receptor complexes.