Comparative Genomic Analysis of Rapidly Evolving SARS-CoV-2 Reveals Mosaic Pattern of Phylogeographical Distribution

Abstract

The outbreak of coronavirus disease 2019 (COVID-19) that started in Wuhan, China, in December 2019 has spread worldwide, emerging as a global pandemic. The severe respiratory pneumonia caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has so far claimed more than 0.38 million lives and has impacted human lives worldwide. However, as the novel SARS-CoV-2 virus displays high transmission rates, the underlying genomic severity is required to be fully understood. We studied the complete genomes of 95 SARS-CoV-2 strains from different geographical regions worldwide to uncover the pattern of the spread of the virus. We show that there is no direct transmission pattern of the virus among neighboring countries, suggesting that its spread is a result of travel of infected humans to different countries. We revealed unique single nucleotide polymorphisms (SNPs) in nonstructural protein 13 (nsp13), nsp14, nsp15, and nsp16 (ORF1b polyproteins) and in the S-protein within 10 viral isolates from the United States. These viral proteins are involved in RNA replication and binding with the human receptors, indicating that the viral variants that are circulating in the population of the United States are different from those circulating in the populations of other countries. In addition, we found an amino acid addition in nsp16 (mRNA cap-1 methyltransferase) of a U.S. isolate (GenBank accession no. MT188341.1) leading to a shift in the amino acid frame from position 2540 onward. Through comparative structural analysis of the wild-type and mutant proteins, we showed that this addition of a phenylalanine residue renders the protein in the mutant less stable, which might affect mRNA cap-1 methyltransferase function. We further analyzed the SARS-CoV-2–human interactome, which revealed that the interferon signaling pathway is targeted by orf1ab during infection and that it also interacts with NF-κB-repressing factor (NKRF), which is a potential regulator of interleukin-8 (IL-8). We propose that targeting this interaction may subsequently improve the health condition of COVID-19 patients. Our analysis also emphasized that SARS-CoV-2 manipulates spliceosome machinery during infection; hence, targeting splicing might affect viral replication. In conclusion, the replicative machinery of SARS-CoV-2 is targeting interferon and the notch signaling pathway along with spliceosome machinery to evade host challenges. IMPORTANCE The COVID-19 pandemic continues to storm the world, with over 6.5 million cases worldwide. The severity of the disease varies with the territories and is mainly influenced by population density and age factor. In this study, we analyzed the transmission pattern of 95 SARS-CoV-2 genomes isolated from 11 different countries. Our study also revealed several nonsynonymous mutations in ORF1b and S-proteins and the impact on their structural stability. Our analysis showed the manipulation of host system by viral proteins through SARS-CoV-2–human protein interactome, which can be useful to understand the impact of virus on human health.

Diet, Gut Microbiota and COVID-19

“…Briefly, it can be concluded that the high fatality rate in Western countries as compared to India, during the lockdown, can be attributed to (1) their animal based diet which increases dysbiosis, hence increasing the pro-inflammatory cytokines resulting in cytokine storm in contrast to the Sattvic diet of the Indian culture including plant based diet and use of traditional medicine as recommended by the Ministry of AYUSH (Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homeopathy), Government of India [58]; (2) the unhealthy dietary habits during lockdown, especially attributed to limited access to fresh grocery shopping, thus resulting in an increase in underlying conditions; (3) the late implementation of lockdown in contrast to the timely implementation of lockdown by the Government of India; (4) the possibility of a more virulent variant of COVID-19 strain prevalent in Western countries in comparison to that prevalent in India due to high mutation rate in the genome of SARS-CoV-2 virus [59,60] and; (5) India, being a developing country, is more exposed to infections as compared to the developed nations, thereby resulting in priming of their immune response against a wide variety of microbes leading to a better immune status than that observed in the Western population.…”

A hijack mechanism of Indian SARS-CoV-2 isolates for relapsing contemporary antiviral therapeutics

“…SARS-CoV-2 isolates are distributed non-geographically with the prevalence of single nucleotide mutations as the major genomic variations. Genetic variance analyses revealed some subtypes, deleterious, and frequent mutation events in SARS-CoV-2 isolates [ [8] , [9] , [10] , [11] ]. Therefore, the emergence of new mutations in SARS-CoV-2 may force the subsequent establishment of a new escape or hijack mechanism for antivirals.…”

Comparative Genomics and Integrated Network Approach Unveiled Undirected Phylogeny Patterns, Co-mutational Hotspots, Functional Crosstalk and Regulatory Interactions in SARS-CoV-2

“…In our previous study, we reported a mosaic pattern of phylogenetic clustering of 95 genomes of SARS-COV-2 isolated from different geographical locations (5). Strains belonging to one country were found clustered with distant countries strains but not with the neighboring one.…”

“…In addition, the genome of SARS-CoV-2 comprises of ORF3a, ORF6, ORF7a, ORF7b, ORF8 and ORF9 genes encoding six accessory proteins, flanked by 5’ and 3’ UTRs (1). In our previous study (5), a higher mutational rate in the genomes from different geographical locations around the world by accumulation of Single Nucleotide Polymorphisms (SNPs) was reported. Even during these early stages of the global pandemic, genomic surveillance has been used to differentiate circulating strains into distinct, geographically based lineages (6).…”