The study for the persistent infection of cytomegalovirus in the developing cerebral neuron

巨细胞病毒（CMV）是人类发育性脑疾病的主要病毒原因。在小鼠巨细胞病毒（MCMV）感染新生小鼠期间，病毒早期抗原（El，El基因的产物; M112/113）在非神经元细胞的El消失后持续存在于海马（HP）和大脑皮质（CX）的神经元中。我们构建了重组MCMV（rMCMV 1373或rMCMV 448），其表达的EGFP是由全长（1373 nt）或截短（448 nt）的el-pro片段控制的。我们研究了在rMCMV感染发育中的小鼠脑和原代神经元培养物期间，神经元和非神经元细胞在原位el-pro激活的差异。 关于我们 tigens（IE 1、IE 3和E1）不仅在室周区（PV）的非神经元细胞中表达，而且在HP和CX的神经元中也有表达。在11 dpi抗原消失PV，但坚持只在神经元。在rMCMV 1373感染的脑中，EGFP表达的动力学与El相同。而在rMCMV 448感染的脑中，EGFP在非神经元细胞中清楚地检测到，直到7 dpi，但在神经元中在任何时间都没有，尽管神经元E1表达足够。在rMCMV 1373感染的原代神经元培养物中，EGFP也优先在神经元中被检测到，但在rMCMV 448感染的神经元中很少检测到。然而，在全长el-pro片段的上游区域从-449到-1373 nt似乎是el-pro的神经元特异性激活所必需的。推测这种独特的神经元el-pro激活可能与病毒嗜神经性和神经发病机制密切相关。少

Cytomegalovirus (CMV) is the leading viral cause of developmental brain disorders in humans. During murine CMV (MCMV) infection of newborn mice, viral early-antigen (El, product of el gene ; M112/113) persisted in neurons of hippocampus (HP) and cerebral cortex (CX) after disappearance of El from non-neuronal cells. Furthermore, neuron-specific activation of MCMV-el promoter (el-pro) in our transgenic mice suggests that a unique el-pro activation likely occurs in developing neurons and may be an important factor for viral neuropathogenesis.We have constructed recombinant MCMV (rMCMV1373 or rMCMV448), which expresses EGFP as a reporter under control of full-length (1373 nt) or truncated (448 nt) el-pro fragment. We have investigated differences in el-pro activation between neurons and non-neuronal cells, in situ, during rMCMV infection of developing mouse brains and primary neuronal cultures.Among any brains infected with wild-type MCMV or rMCMVs, at 7 days-post-infection (dpi) viral an … More tigens (IE1, IE3 and E1) were expressed not only in non-neuronal cells of periventricular area (PV) but also in neurons of HP and CX. At 11 dpi antigens disappeared from PV but persisted exclusively in neurons. In rMCMV 1373-infected brains, kinetics of EGFP expression was the same as that of El. While in rMCMV 448-infected brains EGFP was clearly detected in non-neuronal cells until 7dpi, but not in neurons at any time despite the enough neuronal E1 expression. In rMCMV 1373-infected primary neuronal cultures, EGFP was also preferentially detected in neurons, but very scarcely in rMCMV 448-infected neurons.Our results suggest that IE3-binding sites in truncated el-pro fragment is involved in sufficient el-pro activation in non-neuronal cells as reported previously. However, upstream region from -449 to -1373 nt in full-length el-pro fragment seems to be necessary for neuron-specific activation of el-pro. It is supposed that this unique neuronal el-pro activation may be closely associated with viral neurotropism and neuropathogenesis. Less