RT Journal Article SR Electronic(1) A1 Kojima, Isshu A1 Izumi, Fumiki A1 Ozawa, Makoto A1 Fujimoto, Yoshikazu A1 Okajima, Misuzu A1 Ito, Naoto A1 Sugiyama, Makoto A1 Masatani, TatsunoriYR 2021 T1 Analyses of cell death mechanisms related to amino acid substitution at position 95 in the rabies virus matrix protein JF Journal of General Virology, VO 102 IS 4 OP SP 001594 DO https://doi.org/10.1099/jgv.0.001594 PB Microbiology Society, SN 1465-2099, AB We previously reported that the avirulent fixed rabies virus strain Ni-CE induces a clear cytopathic effect in mouse neuroblastoma cells, whereas its virulent progenitor, the Nishigahara strain, does not. Infection with Nishigahara and Ni-CE mutants containing a single amino acid substitution in the matrix protein (M) demonstrated that the amino acid at position 95 of M (M95) is a cytopathic determinant. The characteristics of cell death induced by Ni-CE infection resemble those of apoptosis (rounded and shrunken cells, DNA fragmentation), but the intracellular signalling pathway for this process has not been fully investigated. In this study, we aimed to elucidate the mechanism by which M95 affects cell death induced by human neuroblastoma cell infection with the Nishigahara, Ni-CE and M95-mutated strains. We demonstrated that the Ni-CE strain induced DNA fragmentation, cell membrane disruption, exposure of phosphatidylserine (PS), activation of caspase-3/7 and anti-poly (ADP-ribose) polymerase 1 (PARP-1) cleavage, an early apoptosis indicator, whereas the Nishigahara strain did not induce DNA fragmentation, caspase-3/7 activation, cell membrane disruption, or PARP-1 cleavage, but did induce PS exposure. We also demonstrated that these characteristics were associated with M95 using M95-mutated strains. However, we found that Ni-CE induced cell death despite the presence of a caspase inhibitor, Z-VAD-FMK. In conclusion, our data suggest that M95 mutation-related cell death is caused by both the caspase-dependent and -independent pathways., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.001594