A peptide inhibitor of exportin1 blocks shuttling of the adenoviral E1B 55 kDa protein but not export of viral late mRNAs

AbstractThe human subgroup C adenoviral E1B 55 kDa and E4 Orf6 proteins are required for efficient nuclear export of viral late mRNAs, but the cellular pathway that mediates such export has not been identified. As a first step to develop a general approach to address this issue, we have assessed the utility of cell-permeable peptide inhibitors of cellular export receptors. As both E1B and E4 proteins have been reported to contain a leucine-rich nuclear export signal (NES), we synthesized a cell-permeable peptide containing such an NES. This peptide induced substantial inhibition of export of the E1B protein, whereas a control, non-functional peptide did not. However, under the same conditions, the NES peptide had no effect on export of viral late mRNAs. These observations establish that viral late mRNAs are not exported by exportin1, as well as the value of peptide inhibitors in investigation of mRNA export regulation in adenovirus-infected cells

A Microfluidic Chamber for Analysis of Neuron-to-Cell Spread and Axonal Transport of an Alpha-Herpesvirus

Alpha-herpesviruses, including herpes simplex virus and pseudorabies virus (PRV), infect the peripheral nervous system (PNS) of their hosts. Here, we describe an in vitro method for studying neuron-to-cell spread of infection as well as viral transport in axons. The method centers on a novel microfluidic chamber system that directs growth of axons into a fluidically isolated environment. The system uses substantially smaller amounts of virus inoculum and media than previous chamber systems and yet offers the flexibility of applying multiple virology and cell biology assays including live-cell optical imaging. Using PRV infection of cultured PNS neurons, we demonstrate that the microfluidic chamber recapitulates all known facets of neuron-to-cell spread demonstrated in animals and other compartmented cell systems

Quantitative analysis of the GAL4/UAS system in Drosophila oogenesis

The GAL4/UAS system is extensively used for targeted gene expression in Drosophila, but the strength of the GAL4 drivers and their effects on target genes are rarely quantified. Quantitative information about the strength of the perturbations introduced by the GAL4/UAS system would further expand the usefulness of the GAL4/UAS system in studying gene functions and developmental processes. We have developed an assay to determine the relative level of expression for target genes tagged with green fluorescent protein (GFP). Our assay enables the relative quantitation of fluorescent proteins within specific cell types and developmental time windows in living eggs/embryos, and permits the analysis of samples from a broad expression range. We illustrate the assay using a panel of four GAL4 drivers and three UAS responder lines in Drosophila oogenesis, discuss the issues associated with the interpretation of the quantitative data, and correlate our results with the analysis of the GAL4/UAS system at the transcript level. The imaging-based strategy described here can be used to quantify other GAL4 drivers in Drosophila and other organisms