Partial Alleviation of Homologous Superinfection Exclusion of SeMNPV Latently Infected Cells by G1 Phase Infection and G2/M Phase Arrest

• Published in: Viruses Vol. 16; no. 5; p. 736
• Main Authors: Fu, Qi-Ming, Fang, Zheng, Ren, Lou, Wu, Qing-Shan, Zhang, Jun-Bo, Liu, Qiu-Ping, Tan, Lei-Tao, Weng, Qing-Bei
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-05-2024
• Subjects: Animals; Baculoviridae; Cell cycle; cell cycle arrest; Cell growth; Cell Line; Cell proliferation; Cyclin B; Cyclin-dependent kinases; DNA biosynthesis; DNA synthesis; Flow cytometry; G1 Phase; G2 Phase Cell Cycle Checkpoints; Genes; Genetic engineering; Genomes; Health aspects; Herpes viruses; Hydroxyurea; Infections; Insecticides; Kinases; Latent infection; Light microscopy; Nocodazole; Nucleopolyhedroviruses - physiology; Occlusion bodies; Proteins; Replication; S phase; SeMNPV; Spodoptera - virology; Spodoptera exigua; Superinfection; Superinfection - virology; superinfection exclusion; Viral infections; Virus Replication; Viruses; China; United States > US; superinfection exclusion; SeMNPV; cell cycle arrest; latent infection; cell cycle; Spodoptera exigua
• DOI: 10.3390/v16050736
• EISSN: 1999-4915

Viral infection can regulate the cell cycle, thereby promoting viral replication. Hijacking and altering the cell cycle are important for the virus to establish and maintain a latent infection. Previously, Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV)-latently infected P8-Se301-C1 cells, which grew more slowly than Se301 cells and interfered with homologous SeMNNPV superinfection, were established. However, the effects of latent and superinfection with baculoviruses on cell cycle progression remain unknown. In this study, the cell cycle profiles of P8-Se301-C1 cells and SeMNPV or Autographa californica multiple nucleopolyhedrovirus (AcMNPV)-infected P8-Se301-C1 cells were characterized by flow cytometry. The results showed that replication-related genes
,
, and
were down-regulated (
< 0.05) in P8-Se301-C1 cells, and the S phase of P8-Se301-C1 cells was longer than that of Se301 cells. P8-Se301-C1 cells infected with SeMNPV did not arrest in the G2/M phase or affect the expression of
and cyclin-dependent kinase 1 (
). Furthermore, when P8-Se301-C1 cells were infected with SeMNPV after synchronized treatment with hydroxyurea and nocodazole, light microscopy and qRT-PCR analysis showed that, compared with unsynchronized cells and S and G2/M phase cells, SeMNPV-infected P8-Se301-C1 cells in G1 phase induced G2/M phase arrest, and the amount of virus adsorption and intracellular viral DNA replication were significantly increased (
< 0.05). In addition, budded virus (BV) production and occlusion body (OB)-containing cells were both increased at 120 h post-infection (
< 0.05). The expression of
and
was significantly down-regulated at 48 h post-infection (
< 0.05). Finally, the arrest of SeMNPV-infected G1 phase cells in the G2/M phase increased BV production (
< 0.05) and the number of OB-containing cells. In conclusion, G1 phase infection and G2/M arrest are favorable to SeMNPV proliferation in P8-Se301-C1 cells, thereby alleviating the homologous superinfection exclusion. The results contribute to a better understanding of the relationship between baculoviruses and insect cell cycle progression and regulation.