Analysis of RNA transport in Xenopus oocytes and mammalian cells

The SARS-CoV-2 ORF6 protein inhibits nuclear export of mRNA and spliceosomal U snRNA

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 19 (COVID-19). SARS-CoV-2 infection suppresses host innate immunity and impairs cell viability. Among the viral proteins, ORF6 exhibits potent interferon (IFN) antagonistic activity and cellular toxicity. It also interacts with the RNA export factor RAE1, which bridges the nuclear pore complex and nuclear export receptors, suggesting an effect on RNA export. Using the Xenopus oocyte microinjection system, I found that ORF6 blocked the export of not only mRNA but also spliceosomal U snRNA. I further demonstrated that ORF6 affects the interaction between RAE1 and nuclear export receptors and inhibits the RNA binding of RAE1. These effects of ORF6 may cumulatively block the export of several classes of RNA. I also found that ORF6 binds RNA and forms oligomers. These findings provide insights into the suppression of innate immune responses and the reduction in cell viability caused by SARS-CoV-2 infection, contributing to the development of antiviral drugs targeting ORF6.

Development of core-collections for Guizhou tea genetic resources and GWAS of leaf size using SNP developed by genotyping-by-sequencing

An accurate depiction of the genetic relationship, the development of core collection, and genome-wide association analysis (GWAS) are key for the effective exploitation and utilization of genetic resources. Here, genotyping-by-sequencing (GBS) was used to characterize 415 tea accessions mostly collected from the Guizhou region in China. A total of 30,282 high-quality SNPs was used to estimate the genetic relationships, develop core collections, and perform GWAS. We suggest 198 and 148 accessions to represent the core set and mini-core set, which consist of 47% and 37% of the whole collection, respectively, and contain 93–95% of the total SNPs. Furthermore, the frequencies of all alleles and genotypes in the whole set were very well retained in the core set and mini-core set. The 415 accessions were clustered into 14 groups and the core and the mini-core collections contain accessions from each group, species, cultivation status and growth habit. By analyzing the significant SNP markers associated with multiple traits, nine SNPs were found to be significantly associated with four leaf size traits, namely MLL, MLW, MLA and MLSI (P < 1.655E−06). This study characterized the genetic distance and relationship of tea collections, suggested the core collections, and established an efficient GWAS analysis of GBS result.