P58IPK, a Plant Ortholog of Double-Stranded RNA-Dependent Protein Kinase PKR Inhibitor, Functions in Viral Pathogenesis

AbstractP58IPK is a cellular inhibitor of the mammalian double-stranded RNA-activated protein kinase (PKR). Here we provide evidence for the existence of its homolog in plants and its role in viral infection at the organism level. Viral infection of P58IPK-silenced Nicotiana benthamiana and Arabidopsis knockouts leads to host death. This host cell death is associated with phosphorylation of the α subunit of eukaryotic translation initiation factor (eIF-2α). Loss of P58IPK leads to reduced virus titer, suggesting that wild-type P58IPK protein plays an important role in viral pathogenesis. Although our complementation results using mammalian P58IPK suggest conservation of the P58IPK pathway in plants and animals, its biological significance seems to be different in these two systems. In animals, P58IPK is recruited by the influenza virus to limit PKR-mediated innate antiviral response. In plants, P58IPK is required by viruses for virulence and therefore functions as a susceptibility factor

Mathematics Is Biology's Next Microscope, Only Better; Biology Is Mathematics' Next Physics, Only Better

Joel Cohen offers a historical and prospective analysis of the relationship between mathematics and biolog

Virus-induced gene complementation reveals a transcription factor network in modulation of tomato fruit ripening

Plant virus technology, in particular virus-induced gene silencing, is a widely used reverse- and forward-genetics tool in plant functional genomics. However the potential of virus technology to express genes to induce phenotypes or to complement mutants in order to understand the function of plant genes is not well documented. Here we exploit Potato virus X as a tool for virus-induced gene complementation (VIGC). Using VIGC in tomato, we demonstrated that ectopic viral expression of LeMADS-RIN, which encodes a MADS-box transcription factor (TF), resulted in functional complementation of the non-ripening rin mutant phenotype and caused fruits to ripen. Comparative gene expression analysis indicated that LeMADS-RIN up-regulated expression of the SBP-box (SQUAMOSA promoter binding protein-like) gene LeSPL-CNR, but down-regulated the expression of LeHB-1, an HD-Zip homeobox TF gene. Our data support the hypothesis that a transcriptional network may exist among key TFs in the modulation of fruit ripening in tomato

E2F1 and p53 Are Dispensable, whereas p21Waf1/Cip1 Cooperates with Rb to Restrict Endoreduplication and Apoptosis during Skeletal Myogenesis

AbstractWe describe temporal and genetic analyses of partially rescued Rb mutant fetuses, mgRb:Rb−/−, that survive to birth and reveal specific defects in skeletal muscle differentiation. We show that in the absence of Rb, these fetuses exhibit increased apoptosis, bona fide endoreduplication, and incomplete differentiation throughout terminal myogenesis. These defects were further augmented in composite mutant fetuses, mgRb:Rb−/−:p21−/−, lacking both Rb and the cyclin-dependent kinase inhibitor p21Waf1/Cip1. Although E2F1 and p53 mediate ectopic DNA synthesis and cell death in several tissues in Rb mutant embryos, both endoreduplication and apoptosis persisted in mgRb:Rb−/−:E2F1−/− and mgRb:Rb−/−:p53−/− compound mutant muscles. Thus, combined inactivation of Rb and p21Waf1/Cip1 augments endoreduplication and apoptosis, whereas E2F1 and p53 are dispensable during aberrant myogenesis in Rb-deficient fetuses

Virus-induced gene silencing database for phenomics and functional genomics in Nicotiana benthamiana

Virus-induced gene silencing (VIGS) is an important forward and reverse genetics method for the study of gene function in many plant species, especially Nicotiana benthamiana. However, despite the widespread use of VIGS, a searchable database compiling the phenotypes observed with this method is lacking. Such a database would allow researchers to know the phenotype associated with the silencing of a large number of individual genes without experimentation. We have developed a VIGS phenomics and functional genomics database (VPGD) that has DNA sequence information derived from over 4,000 N. benthamiana VIGS clones along with the associated silencing phenotype for approximately 1,300 genes. The VPGD has a built-in BLAST search feature that provides silencing phenotype information of specific genes. In addition, a keyword-based search function could be used to find a specific phenotype of interest with the corresponding gene, including its Gene Ontology descriptions. Query gene sequences from other plant species that have not been used for VIGS can also be searched for their homologs and silencing phenotype in N. benthamiana. VPGD is useful for identifying gene function not only in N. benthamiana but also in related Solanaceae plants such as tomato and potato. The database is accessible at http://vigs.noble.org.Noble Research Institute and NSF IOS-102564

Psychotic symptoms in young adults exposed to childhood trauma - A 20 year follow-up study

Childhood adversity has been shown to increase the risk of psychotic symptoms in adult life. However, there are no previous studies looking at the association between experiencing a natural disaster during childhood and the development of psychotic symptoms in young adulthood. Eight hundred and six bushfire-exposed children and 725 control children were evaluated following the 1983 South Australian bushfires. Five hundred and twenty nine (65.6%) of the bushfire group and 464 (64%) controls participated in a follow up study 20 years later. Childhood data on emotional and behavioural disorders and dysfunctional parenting was available. The adult assessment included the Australian National Health and Well-Being psychosis screen and detailed information about trauma, childhood adversity and alcohol and cannabis abuse. 5.6% of subjects responded positively to the psychosis screen and 2.6% responded positively to a further probe question. Psychotic symptoms were more common in subjects exposed to a greater number of traumas, and were associated with higher rates of childhood adversity, emotional and behavioural disturbance, dysfunctional parenting, and alcohol and cannabis abuse. Subjects exposed to bushfires as children did not have a greater risk of psychosis. Our results indicate that exposure to multiple traumas, rather than a single major trauma, increases the risk of later psychosis.Cherrie Galletly, Miranda Van Hooff, Alexander McFarlan