Whole-Genome Sequencing of Vero E6 (VERO C1008) and Comparative Analysis of Four Vero Cell Sublines

Kazuhiro Konishi; Toshiyuki Yamaji; Chisato Sakuma; Fumio Kasai; Toshinori Endo; Arihiro Kohara; Kentaro Hanada; Naoki Osada

doi:10.3389/fgene.2022.801382

Whole-Genome Sequencing of Vero E6 (VERO C1008) and Comparative Analysis of Four Vero Cell Sublines

Front Genet. 2022 Mar 22:13:801382. doi: 10.3389/fgene.2022.801382. eCollection 2022.

Authors

Kazuhiro Konishi¹, Toshiyuki Yamaji², Chisato Sakuma², Fumio Kasai³, Toshinori Endo⁴, Arihiro Kohara³, Kentaro Hanada², Naoki Osada⁴

Affiliations

¹ Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan.
² Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan.
³ Laboratory of Cell Cultures, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan.
⁴ Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan.

Abstract

The Vero cell line is an immortalized cell line established from kidney epithelial cells of the African green monkey. A variety of Vero sublines have been developed and can be classified into four major cell lineages. In this study, we determined the whole-genome sequence of Vero E6 (VERO C1008), which is one of the most widely used cell lines for the proliferation and isolation of severe acute respiratory syndrome coronaviruses (SARS-CoVs), and performed comparative analysis among Vero JCRB0111, Vero CCL-81, Vero 76, and Vero E6. Analysis of the copy number changes and loss of heterozygosity revealed that these four sublines share a large deletion and loss of heterozygosity on chromosome 12, which harbors type I interferon and CDKN2 gene clusters. We identified a substantial number of genetic differences among the sublines including single nucleotide variants, indels, and copy number variations. The spectrum of single nucleotide variants indicated a close genetic relationship between Vero JCRB0111 and Vero CCL-81, and between Vero 76 and Vero E6, and a considerable genetic gap between the former two and the latter two lines. In contrast, we confirmed the pattern of genomic integration sites of simian endogenous retroviral sequences, which was consistent among the sublines. We identified subline-specific/enriched loss of function and missense variants, which potentially contribute to the differences in response to viral infection among the Vero sublines. In particular, we identified four genes (IL1RAP, TRIM25, RB1CC1, and ATG2A) that contained missense variants specific or enriched in Vero E6. In addition, we found that V739I variants of ACE2, which functions as the receptor for SARS-CoVs, were heterozygous in Vero JCRB0111, Vero CCL-81, and Vero 76; however, Vero E6 harbored only the allele with isoleucine, resulting from the loss of one of the X chromosomes.

Keywords: Vero E6; Vero cells; cell lines; cell substrate; genome sequencing.