Molecular characteristics of VP4 and VP7 of a Rotavirus A in cattle in Yunnan Province, China

Abstract

Rotavirus is classified within the family Reoviridae, subfamily Sedoreovirinae, and the genus Rotavirus. This genus encompasses eight groups, denoted as species A to H, with Group A holding particular significance due to its widespread prevalence among both human and animal populations. Among these, Bovine rotavirus (BoRV) stands out as the leading cause of substantial morbidity, mortality, and economic losses in neonatal calves.Rotavirus is classified within the family Reoviridae, subfamily Sedoreovirinae, and the genus Rotavirus. This genus encompasses eight groups, denoted as species A to H, with Group A holding particular significance due to its widespread prevalence among both human and animal populations. Among these, Bovine rotavirus (BoRV) stands out as the leading cause of substantial morbidity, mortality, and economic losses in neonatal calves. In order to identify the etiology of cattle with diarrheal diseases and further enrich the epidemiological data of bovine rotavirus (BRV) in China, RT-PCR was used to identify virus pathogens from 10 diarrheal cattle fecal samples. Positive samples were inoculated in MA-104 cells, generating stable cytopathologies from the sixth generation. Basic physicochemical properties, structural functions and functions of the VP4/VP7 proteins of the virus were predicted and analyzed by indirect immunofluorescence test (IFA). The results identified the isolated virus was BRV and it was named RVA/Cattle/CHN/YN1/2021/G8P. Following RT-PCR amplification, sequencing and splicing of 11 gene segments of this strain, homology and typing analyses were conducted. A genetic tree of isolated strains was constructed based on VP7 and VP4 sequences, and the genetic evolutionary relationship and the variation of amino acid sequences were analyzed. The results showed that among 11 fragments of the YN-1 genome, 5 segments showed high nucleotide identity with a deer strain, 2 segments with human, 1 with U.S. vaccine strain; 7 segments highly identified with a U.S. strain, among them 5 segments were highly identified with strain C/Cervidae/United States/14-02218-2/2014. Bioinformatics analysis results indicated that both VP4 and VP7 proteins are stable, hydrophilic, transmembrane and non-secretory proteins. The number of O-glycosylation, N-glycosylation, phosphorylation sites were 150 and 59, 3, 102 and 34 in VP4 and VP7, respectively. Subcellular localization is located in the plasma membrane, with α-Spiral and extension as the main structures, with irregular curls and β-The corner running through it. Therefore, the genome constellation of this strain was determined as G8-P[1]-I2-R2-C2-M2-A3-N2-T6-E2-H. The study results lay a foundational work for the development of vaccines, and detection kits, which also support the effective prevention and control of BRV infection in China in the near future.