Kato Akihisa, Shindo Keiko, Maruzuru Yuhei, Kawaguchi Yasushi
Division of Molecular Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan.
J Virol. 2014 Mar;88(5):2775-85. doi: 10.1128/JVI.03300-13. Epub 2013 Dec 18.
Herpes simplex virus 1 (HSV-1) encodes Us3 protein kinase, which is critical for viral pathogenicity in both mouse peripheral sites (e.g., eyes and vaginas) and in the central nervous systems (CNS) of mice after intracranial and peripheral inoculations, respectively. Whereas some Us3 substrates involved in Us3 pathogenicity in peripheral sites have been reported, those involved in Us3 pathogenicity in the CNS remain to be identified. We recently reported that Us3 phosphorylated HSV-1 dUTPase (vdUTPase) at serine 187 (Ser-187) in infected cells, and this phosphorylation promoted viral replication by regulating optimal enzymatic activity of vdUTPase. In the present study, we show that the replacement of vdUTPase Ser-187 by alanine (S187A) significantly reduced viral replication and virulence in the CNS of mice following intracranial inoculation and that the phosphomimetic substitution at vdUTPase Ser-187 in part restored the wild-type viral replication and virulence. Interestingly, the S187A mutation in vdUTPase had no effect on viral replication and pathogenic effects in the eyes and vaginas of mice after ocular and vaginal inoculation, respectively. Similarly, the enzyme-dead mutation in vdUTPase significantly reduced viral replication and virulence in the CNS of mice after intracranial inoculation, whereas the mutation had no effect on viral replication and pathogenic effects in the eyes and vaginas of mice after ocular and vaginal inoculation, respectively. These observations suggested that vdUTPase was one of the Us3 substrates responsible for Us3 pathogenicity in the CNS and that the CNS-specific virulence of HSV-1 involved strict regulation of vdUTPase activity by Us3 phosphorylation.
Herpes simplex virus 1 (HSV-1) encodes a viral protein kinase Us3 which is critical for pathogenicity both in peripheral sites and in the central nervous systems (CNS) of mice following peripheral and intracranial inoculations, respectively. Whereas some Us3 substrates involved in Us3 pathogenicity in peripheral sites have been reported, those involved in Us3 pathogenicity in the CNS remain to be identified. Here, we report that Us3 phosphorylation of viral dUTPase (vdUTPase) at serine 187 (Ser-187), which has been shown to promote the vdUTPase activity, appears to be critical for viral virulence in the CNS but not for pathogenic effects in peripheral sites. Since HSV proteins critical for viral virulence in the CNS are, in almost all cases, also involved in viral pathogenicity at peripheral sites, this phosphorylation event is a unique report of a specific mechanism involved in HSV-1 virulence in the CNS.
单纯疱疹病毒1型（HSV-1）编码Us3蛋白激酶，该激酶对于病毒在小鼠外周部位（如眼睛和阴道）以及分别在颅内和外周接种后小鼠中枢神经系统（CNS）中的致病性至关重要。虽然已经报道了一些参与外周部位Us3致病性的Us3底物，但参与中枢神经系统中Us3致病性的底物仍有待确定。我们最近报道，在感染细胞中，Us3使HSV-1 dUTP酶（vdUTPase）的丝氨酸187（Ser-187）磷酸化，这种磷酸化通过调节vdUTPase的最佳酶活性促进病毒复制。在本研究中，我们表明，用丙氨酸取代vdUTPase的Ser-187（S187A）显著降低了颅内接种后小鼠中枢神经系统中的病毒复制和毒力，并且在vdUTPase的Ser-187处进行模拟磷酸化的取代部分恢复了野生型病毒的复制和毒力。有趣的是，vdUTPase中的S187A突变分别对眼部和阴道接种后小鼠眼睛和阴道中的病毒复制和致病作用没有影响。同样，vdUTPase中的酶失活突变显著降低了颅内接种后小鼠中枢神经系统中的病毒复制和毒力，而该突变分别对眼部和阴道接种后小鼠眼睛和阴道中的病毒复制和致病作用没有影响。这些观察结果表明，vdUTPase是负责中枢神经系统中Us3致病性的Us3底物之一，并且HSV-1的中枢神经系统特异性毒力涉及通过Us3磷酸化对vdUTPase活性的严格调节。
单纯疱疹病毒1型（HSV-1）编码一种病毒蛋白激酶Us3，该激酶分别对于外周接种和颅内接种后小鼠外周部位和中枢神经系统（CNS）中的致病性至关重要。虽然已经报道了一些参与外周部位Us3致病性的Us3底物，但参与中枢神经系统中Us3致病性的底物仍有待确定。在这里，我们报道，已证明能促进vdUTPase活性的病毒dUTP酶（vdUTPase）在丝氨酸187（Ser-187）处的Us3磷酸化似乎对中枢神经系统中的病毒毒力至关重要，但对外周部位的致病作用并非如此。由于几乎在所有情况下，对中枢神经系统中病毒毒力至关重要的HSV蛋白也参与外周部位的病毒致病性，因此这种磷酸化事件是关于HSV-1在中枢神经系统中毒力的一种特定机制的独特报道。
