Molecular biology of the SARs-CoV-2 spike protein: A review of current knowledge.

The global coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to an unprecedented worldwide public health emergency. Despite the concerted efforts of the scientific field, by April 25, 2021, SARS-CoV-2 had spread to over 192 countries/regions, causing more than 146 million confirmed cases including 31 million deaths. For now, an established treatment for patients with COVID-19 remains unavailable. The key to tackling this pandemic is to understand the mechanisms underlying its infectivity and pathogenicity. As a predominant focus, the coronavirus spike (S) protein is the key determinant of host range, infectivity, and pathogenesis. Thereby comprehensive understanding of the sophisticated structure of SARS-CoV-2 S protein may provide insights into possible intervention strategies to fight this ongoing global pandemic. Herein, we summarize the current knowledge of the molecular structural and functional features of SARS-CoV-2 S protein as well as recent updates on the cell entry mechanism of the SARS-CoV-2, paving the way for exploring more structure-guided strategies against SARS-CoV-2.

Mutation analysis of 21 autosomal short tandem repeats in Han population from Hunan, China.

Background: Short tandem repeats (STRs) are powerful genetic markers widely used in human genetics. Population data and locus-specific mutation rates of STRs are crucial for the evaluation and interpretation of genetic evidence in forensic and population genetics.Aim: To investigate the mutation rates of 21 autosomal STRs in a population from central south China.Subjects and methods: This study analysed 3420 paternity cases with a Combined Paternity Index >10,000 from Han population in Hunan. A total of 68,743 meiotic transfers were analysed and 62 mutations were identified.Results: The overall mutation rate of STR loci was 0.9 × 10-3 (95% CI, 0.0007-0.0011) and the locus-specific mutation rates were estimated ranging from 0.0000-0.0023. Locus D1S1656 exhibited the highest mutation rate of 2.3 × 10-3 (95% CI, 0.0005-0.0006), followed by D12S391 with a mutation rate of 2.0 × 10-3 (95% CI, 0.0007-0.0044). No mutation was observed at TPOX, D2S1338 or Penta D. One-step mutation cases accounted for 96.77% of total mutations and the ratio of paternal vs maternal mutations was ∼4.85:1. Inter-population comparisons of locus-specific mutation rates of several STRs revealed significant differences between Han in Hunan and Han in other regions of China. Conclusion: The data justified the use of geographical data in further genetic applications.