Statistical modeling of mRNP transport in dendrites: A comparative analysis of ß-actin and Arc mRNP dynamics.

Localization of messenger RNA (mRNA) in dendrites is crucial for regulating gene expression during long-term memory formation. mRNA binds to RNA-binding proteins (RBPs) to form messenger ribonucleoprotein (mRNP) complexes that are transported by motor proteins along microtubules to their target synapses. However, the dynamics by which mRNPs find their target locations in the dendrite have not been well understood. Here, we investigated the motion of endogenous ß-actin and Arc mRNPs in dissociated mouse hippocampal neurons using the MS2 and PP7 stem-loop systems, respectively. By evaluating the statistical properties of mRNP movement, we found that the aging Lévy walk model effectively describes both ß-actin and Arc mRNP transport in proximal dendrites. A critical difference between ß-actin and Arc mRNPs was the aging time, the time lag between transport initiation and measurement initiation. The longer mean aging time of ß-actin mRNP (~100 s) compared with that of Arc mRNP (~30 s) reflects the longer half-life of constitutively expressed ß-actin mRNP. Furthermore, our model also permitted us to estimate the ratio of newly generated and pre-existing ß-actin mRNPs in the dendrites. This study offers a robust theoretical framework for mRNP transport, which provides insight into how mRNPs locate their targets in neurons.

Flattening the Curve on COVID-19: South Korea's Measures in Tackling Initial Outbreak of Coronavirus.

The spread of coronavirus disease 2019 (COVID-19) is causing an unprecedented crisis around the world, with South Korea being no exception. South Korea experienced a surge of COVID-19 cases on February 19, 2020, but was able to flatten the COVID-19 curve in only 20 days without enforcing lockdown measures that restrict the freedom and movement of people. The actual field experience of the Korean government's COVID-19 response team, who participated in drafting the document "Tackling COVID-19: Health, Quarantine, and Economic Measures: Korean experience," was examined and an in-depth analysis was conducted of the South Korean government's experience dealing with the Middle East respiratory syndrome of 2015. Three prominent factors were identified behind Korea's responses against COVID-19. First, it was crucial that the government responded as 1 team efficiently to cooperate and respond to COVID-19. Second, a novel approach was needed to combat COVID-19 spread. Information and communication technology had a key role in South Korea's strategy to contain COVID-19. Third, an effective response to COVID-19 was possible due to the successful partnership between the general public and state authorities.