Recombinant expression of beak and feather disease virus capsid protein and assembly of virus-like particles in Nicotiana benthamiana

Background: Beak and feather disease virus (BFDV) is an important disease causing agent affecting psittacines. BFDV is highly infectious and can present as acute, chronic or subclinical disease. The virus causes immunodeficiency and is often associated with secondary infections. No commercial vaccine is available and yields of recombinant BFDV capsid protein (CP) expressed in insect cells and bacteria are yet to be seen as commercially viable, although both systems produced BFDV CP that could successfully assemble into virus-like particles (VLPs). Plants as expression systems are increasingly becoming favourable for the production of region-specific and niche market products. The aim of this study was to investigate the formation and potential for purification of BFDV VLPs in Nicotiana benthamiana. Methods: The BFDV CP was transiently expressed in N. benthamiana using an Agrobacterium-mediated system and plant expression vectors that included a bean yellow dwarf virus (BeYDV)-based replicating DNA vector. Plant-produced BFDV CP was detected using immunoblotting. VLPs were purified using sucrose cushion and CsCl density gradient centrifugation and visualised using transmission electron microscopy. Results: In this study we demonstrate that the BFDV CP can be successfully expressed in N. benthamiana, albeit at relatively low yield. Using a purification strategy based on centrifugation we demonstrated that the expressed CP can self-assemble into VLPs that can be detected using electron microscopy. These plant-produced BFDV VLPs resemble those produced in established recombinant expression systems and infectious virions. It is possible that the VLPs are spontaneously incorporating amplicon DNA produced from the replicating BeYDV plant vector. Conclusions: This is the first report of plant-made full-length BFDV CP assembling into VLPs. The putative pseudovirions could be used to further the efficacy of vaccines against BFDV

Health promotion and screening for people with an intellectual disability

People with intellectual disability have significantly worse health than those without, and have a higher level of complex health needs. The life expectancy for men and women is 13 and 20 years shorter, respectively, than the general population. The increasing role of general practice in delivering and coordinating care across health and social care settings requires expert generalist skills to implement an integrated approach to care. This article explores how general practice can improve the health of people with intellectual disability, by making reasonable adjustments within health promotion, disease prevention, screening and detection

Transient backbending behavior in the Ising model with fixed magnetization

The physical origin of the backbendings in the equations of state of finite but not necessarily small systems is studied in the Ising model with fixed magnetization (IMFM) by means of the topological properties of the observable distributions and the analysis of the largest cluster with increasing lattice size. Looking at the convexity anomalies of the IMFM thermodynamic potential, it is shown that the order of the transition at the thermodynamic limit can be recognized in finite systems independently of the lattice size. General statistical mechanics arguments and analytical calculations suggest that the backbending in the caloric curve is a transient behaviour which should not converge to a plateau in the thermodynamic limit, while the first order transition is signalled by a discontinuity in other observables.Comment: 24 pages, 11 figure

JASPer controls interphase histone H3S10 phosphorylation by chromosomal kinase JIL-1 in Drosophila

In flies, the chromosomal kinase JIL-1 is responsible for most interphase histone H3S10 phosphorylation and has been proposed to protect active chromatin from acquiring heterochromatic marks, such as dimethylated histone H3K9 (H3K9me2) and HP1. Here, we show that JIL-1's targeting to chromatin depends on a PWWP domain-containing protein JASPer (JIL-1 Anchoring and Stabilizing Protein). JASPer-JIL-1 (JJ)-complex is the major form of kinase in vivo and is targeted to active genes and telomeric transposons via binding of the PWWP domain of JASPer to H3K36me3 nucleosomes, to modulate transcriptional output. JIL-1 and JJ-complex depletion in cycling cells lead to small changes in H3K9me2 distribution at active genes and telomeric transposons. Finally, we identify interactors of the endogenous JJ-complex and propose that JIL-1 not only prevents heterochromatin formation but also coordinates chromatin-based regulation in the transcribed part of the genome

PWWP2A binds distinct chromatin moieties and interacts with an MTA1-specific core NuRD complex.

Chromatin structure and function is regulated by reader proteins recognizing histone modifications and/or histone variants. We recently identified that PWWP2A tightly binds to H2A.Z-containing nucleosomes and is involved in mitotic progression and cranial-facial development. Here, using in vitro assays, we show that distinct domains of PWWP2A mediate binding to free linker DNA as well as H3K36me3 nucleosomes. In vivo, PWWP2A strongly recognizes H2A.Z-containing regulatory regions and weakly binds H3K36me3-containing gene bodies. Further, PWWP2A binds to an MTA1-specific subcomplex of the NuRD complex (M1HR), which consists solely of MTA1, HDAC1, and RBBP4/7, and excludes CHD, GATAD2 and MBD proteins. Depletion of PWWP2A leads to an increase of acetylation levels on H3K27 as well as H2A.Z, presumably by impaired chromatin recruitment of M1HR. Thus, this study identifies PWWP2A as a complex chromatin-binding protein that serves to direct the deacetylase complex M1HR to H2A.Z-containing chromatin, thereby promoting changes in histone acetylation levels