Trans-Acting RNA–RNA Interactions in Segmented RNA Viruses

RNA viruses represent a large and important group of pathogens that infect a broad range of hosts. Segmented RNA viruses are a subclass of this group that encode their genomes in two or more molecules and package all of their RNA segments in a single virus particle. These divided genomes come in different forms, including double-stranded RNA, coding-sense single-stranded RNA, and noncoding single-stranded RNA. Genera that possess these genome types include, respectively, Orbivirus (e.g., Bluetongue virus), Dianthovirus (e.g., Red clover necrotic mosaic virus) and Alphainfluenzavirus (e.g., Influenza A virus). Despite their distinct genomic features and diverse host ranges (i.e., animals, plants, and humans, respectively) each of these viruses uses trans-acting RNA–RNA interactions (tRRIs) to facilitate co-packaging of their segmented genome. The tRRIs occur between different viral genome segments and direct the selective packaging of a complete genome complement. Here we explore the current state of understanding of tRRI-mediated co-packaging in the abovementioned viruses and examine other known and potential functions for this class of RNA–RNA interaction.

Formin-based control of the actin cytoskeleton during cytokinesis

Cytokinesis, the terminal event in the canonical cell cycle, physically separates daughter cells following mitosis. For cleavage to occur in many eukaryotes, a cytokinetic ring must assemble and constrict between divided genomes. Although dozens of different molecules localize to and participate within the cytokinetic ring, the core machinery comprises linear actin filaments. Accordingly, formins, which nucleate and elongate F-actin (filamentous actin) for the cytokinetic ring, are required for cytokinesis in diverse species. In the present article, we discuss specific modes of formin-based actin regulation during cell division and highlight emerging mechanisms and questions on this topic.

Clonación del gen de la cápside protéica de una cepa colombiana del Virus del Mosaico del Pepino (CMV) para su expresión en plantas por transformación mediante Agrobaderium

<p>Nota de Investigación. </p><p>El Virus del Mosaico del Pepíno (Cucumber Mosaic Virus, CMV) forma parte del grupo Cucumuvirus de la familia romoyiridae:este virus tiene su genoma dividido en tres cadenas positivas de ARN y un ARN-4 subgenómico el cual se genera de la transcripción delARN-3 y sirve como ARN mensajerop aral a síntesisd e proteínad e la cápside (Davies, 1988). EI.CMV puede infectarm ásd e 8oo especieds e plantasy se encuentra distribuido en todo el mundo. </p><p><strong>Cloning of the coat protein gene from a Colombian strain of CMV for its expression in plants using Agrobaderium-mediated transformation</strong></p><p>Research Note.</p><p>Cucumber Mosaic Virus (CMV) is a member of the cucumuvirus group in the Bromoviridaefa mily which membersh ave divided genomes consisting of three positive-strand RNAs and a subgenomic RNA 4 that is generated from the transcription<br />of RNA ¡ and servesa s a messengerR NA for the viral coat protein (Davies, 1988). CMV can infect over 8oo specieso f plants and has a world-wide distribution.</p>

A dendrogram of plant viruses

To facilitate the recognition of plant viruses with similar characteristics a dendrogram of characterized viruses was constructed. The sequence of criteria included: type of nucleic acid; single or double stranded; presence or absence of lipid envelope; helical or nonhelical symmetry; and divided or single genome. Nonhelical RNA viruses with divided genomes were further divided into viruses with one or more than one capsid size. Those with one capsid size were subdivided into viruses with one or more than one sedimenting component. Nonhelical RNA viruses with a single genome were divided according to their RNA size, and their sensitivity to sodium dodecyl sulfate and ethyIenediaminetetraacetic acid.