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Tyrosine phosphorylation of measles virus nucleocapsid protein in persistently infected neuroblastoma cells
1Department of Microbiology and Immunology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel.
Abstract:
Subacute sclerosing panencephalitis is a slowly progressing fatal human disease of the central nervous system which is a delayed sequel of measles virus (MV) infection. A typical pathological feature of this disease is the presence of viral ribonucleocapsid structures in the form of inclusion bodies and the absence of infectious virus or budding viral particles. The mechanisms governing the establishment and maintenance of a persistent MV infection in brain cells are still largely unknown. To understand the mechanisms underlying MV persistence in neuronal cells, a tissue culture model was studied. Clone NS20Y/MS of the murine neuroblastoma C1300 persistently infected with the wild-type Edmonston strain of MV secretes relatively high levels of alpha/beta interferon (IFN). As shown previously, treatment of the persistently infected cultures with anti-IFN serum converted the persistent state into a productive infection indicated by the appearance of multinucleated giant cells. In this study, we have investigated whether alpha/beta IFN produced by NS20Y/MS cells activates cellular protein tyrosine kinases which will induce tyrosine phosphorylating activity specific to virus-infected cells. We present data to show augmented protein tyrosine kinase activity in the persistently infected cells. We demonstrate that the MV N protein is phosphorylated on tyrosine in addition to serine and threonine in the persistent state but not in NS20Y cells acutely infected with MV.
Insights
Subacute sclerosing panencephalitis (SSPE) involves persistent measles virus (MV) infection in the brain. This study reveals that alpha/beta interferon (IFN) in infected cells activates protein tyrosine kinases, leading to MV N protein phosphorylation.
Area of Science:
- Neurovirology
- Cellular Microbiology
- Immunology
Background:
- Subacute sclerosing panencephalitis (SSPE) is a fatal neurological disease following measles virus (MV) infection.
- Persistent MV infection in brain cells, characterized by inclusion bodies and lack of infectious virus, remains poorly understood.
- Alpha/beta interferon (IFN) is secreted by persistently infected neuronal cells and can switch the infection to a productive state.
Purpose of the Study:
- To investigate the role of alpha/beta interferon (IFN) in activating cellular protein tyrosine kinases during persistent MV infection.
- To determine if this activation leads to specific tyrosine phosphorylation in virus-infected cells.
- To elucidate mechanisms of MV persistence in neuronal cells.
Main Methods:
- Utilized a persistent MV infection model in murine neuroblastoma cells (Clone NS20Y/MS).
- Assessed protein tyrosine kinase activity in persistently and acutely infected cells.
- Analyzed the phosphorylation status of the MV N protein using biochemical assays.
Main Results:
- Demonstrated augmented protein tyrosine kinase activity in persistently MV-infected neuronal cells.
- Showed that the MV N protein is phosphorylated on tyrosine residues in the persistent state.
- Confirmed that tyrosine phosphorylation of the MV N protein does not occur in acutely infected cells.
Conclusions:
- Alpha/beta interferon (IFN) produced during persistent MV infection activates cellular protein tyrosine kinases.
- This activation results in specific tyrosine phosphorylation of the MV N protein, a novel finding in the context of SSPE pathogenesis.
- These findings offer insights into the molecular mechanisms underlying MV persistence in the central nervous system.