Topoisomerase 3b is dispensable for replication of a positive-sense RNA virus--murine coronavirus.

A recent study demonstrated that a DNA-RNA dual-activity topoisomerase complex, TOP3B-TDRD3, is required for normal replication of positive-sense RNA viruses, including several human flaviviruses and coronaviruses; and the authors proposed that TOP3B is a target of antiviral drugs. Here we examined this hypothesis by investigating whether inactivation of Top3b can inhibit the replication of a mouse coronavirus, MHV, using cell lines and mice that are inactivated of Top3b or Tdrd3. We found that Top3b-KO or Tdrd3-KO cell lines generated by different CRISPR-CAS9 guide RNAs have variable effects on MHV replication. In addition, we did not find significant changes of MHV replication in brains or lungs in Top3B-KO mice. Moreover, immunostaining showed that Top3b proteins are not co-localized with MHV replication complexes but rather, localized in stress granules in the MHV-infected cells. Our results suggest that Top3b does not have a universal role in promoting replication of positive-sense RNA virus, and cautions should be taken when targeting it to develop anti-viral drugs.

The Impacts and Implications of the COVID-19 Pandemic on the Global Response to Climate Change

The coronavirus disease (COVID-19) pandemic has posed the most severe impact on the global economy and society since World War II. The pandemic has brought into focus how climate change is related with virus transmission and health, and has made the global transition toward low-carbon development more difficult and challenged the implementation of the Paris Agreement. Although the pandemic has significantly reduced carbon emissions and improved the environmental quality in the short term, it is still an unwanted event in the process of pursuing sustainable development;although objectively the pandemic has weakened countries’ efforts in terms of policies and actions to address climate change, the restructuring of global value chains in the post-COVID era has also brought new opportunities for a transition toward green and low-carbon development;although the pandemic has warned people of how important resilient governance and international cooperation is to addressing the crisis, the global climate governance process has come to a complete standstill since the outbreak of COVID-19, attenuating the mutual trust among countries and disabling the leadership in climate governance. The pandemic is a preview of the climate crisis, and it is important to learn from it for a better response. China quickly contained the pandemic within the country, actively resumed work and production, and gained a first-mover advantage in economic recovery. China should maintain strategic focus when pursuing ecological development, enhance the resilience of the socio-economic system, seize the opportunity of transitioning toward low-carbon development by turning the crisis into opportunities, and promote high-quality development within the country while fully engaging in global climate governance to seek ecological progress with other countries. [ABSTRACT FROM AUTHOR] Copyright of Chinese Journal of Urban & Environmental Studies is the property of World Scientific Publishing Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)