A Close-Up Look at PCR

The Polymerase Chain Reaction (PCR) is a fundamental laboratory technique that allows for the amplification of many copies of a desired DNA target sequence. Despite its prevalence, undergraduate students often have poor comprehension about the underlying molecular mechanisms of PCR and the components necessary to carry out the reaction. We designed an interactive modeling activity to help students visualize the underlying molecular processes of denaturation, annealing, and extension, and to see how PCR parallels in vivo DNA replication. During the activity, students mimic denaturation, annealing, and extension by synthesizing DNA strands from individual nucleotides and primers in the 5’ to 3’ direction. Because they carry out three cycles, students construct and observe the intermediate products that lead to the exponential amplification of the target sequence. Instructors can easily assemble kits from relatively inexpensive foam nucleotide pieces, and the models can be reused indefinitely. Field testing with first and second year undergraduates suggested that students productively interacted with the models to improve their understanding of PCR

CAPG is required for Ebola virus infection by controlling virus egress from infected cells

The replication of Ebola virus (EBOV) is dependent upon actin functionality, especially at cell entry through macropinocytosis and at release of virus from cells. Previously, major actin-regulatory factors involved in actin nucleation, such as Rac1 and Arp2/3, were shown important in both steps. However, downstream of nucleation, many other cell factors are needed to control actin dynamics. How these regulate EBOV infection remains largely unclear. Here, we identified the actin-regulating protein, CAPG, as important for EBOV replication. Notably, knockdown of CAPG specifically inhibited viral infectivity and yield of infectious particles. Cell-based mechanistic analysis revealed a requirement of CAPG for virus production from infected cells. Proximity ligation and split-green fluorescent protein reconstitution assays revealed strong association of CAPG with VP40 that was mediated through the S1 domain of CAPG. Overall, CAPG is a novel host factor regulating EBOV infection through connecting actin filament stabilization to viral egress from cells