Ishiwata M, Baba S, Kawashima M, Kosugi I, Kawasaki H, Kaneta M, Tsuchida T, Kozuma S, Tsutsui Y
Department of Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Arch Virol. 2006 Nov;151(11):2181-96. doi: 10.1007/s00705-006-0793-0. Epub 2006 Jun 8.
Murine cytomegalovirus (MCMV) immediate-early (IE) 2 protein has been reported to be dispensable for growth and latency in mice. Therefore, its role in viral pathogenesis and tissue tropism is not known. Here we prepared specific antibodies to the IE2 and IE3 proteins by using fusion proteins expressed in Escherichia coli as antigens. Immunostaining of MCMV-infected cultured fibroblasts revealed IE2 protein to be expressed diffusely in the nucleoplasm similar to the IE1 protein. In contrast, expression of the IE3 protein, 88 kDa, exhibited a punctate pattern in the nucleus in the early phase of infection then diminished. In the brain of neonatal mice infected with MCMV, both IE2 and IE3 proteins were detected immunohistochemically in the cells of the ventricular walls early in infection. When the infection was prolonged, the IE2 protein was expressed in neurons of the cortex and hippocampus, while the IE3 protein was preferentially expressed in glial cells in the early phase of infection, and its levels declined during the infection. These results suggest that the IE2 protein may play a role in persistent infection in neurons, whereas the IE3 protein, expressed preferentially in glial cells, may play the main role in acute infection.
据报道，小鼠巨细胞病毒（MCMV）即刻早期（IE）2蛋白对于小鼠的生长和潜伏并非必需。因此，其在病毒发病机制和组织嗜性中的作用尚不清楚。在这里，我们以在大肠杆菌中表达的融合蛋白为抗原制备了针对IE2和IE3蛋白的特异性抗体。对MCMV感染的培养成纤维细胞进行免疫染色显示，IE2蛋白在核质中呈弥漫性表达，类似于IE1蛋白。相比之下，88 kDa的IE3蛋白在感染早期在细胞核中呈点状分布，随后减少。在感染MCMV的新生小鼠脑中，免疫组化检测发现，在感染早期，心室壁细胞中可检测到IE2和IE3蛋白。当感染持续时，IE2蛋白在皮质和海马体的神经元中表达，而IE3蛋白在感染早期优先在胶质细胞中表达，且其水平在感染过程中下降。这些结果表明，IE2蛋白可能在神经元的持续感染中起作用，而优先在胶质细胞中表达的IE3蛋白可能在急性感染中起主要作用。
