The protamine-like DNA-binding protein P6.9 epigenetically up-regulates Autographa californica multiple nucleopolyhedrovirus gene transcription in the late infection phase
The protamine-like DNA-binding protein P6.9 epigenetically up-regulates Autographa californica multiple nucleopolyhedrovirus gene transcription in the late infection phase
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DOI：
10.1007/s12250-012-3229-x
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发表时间：
2012-01
影响因子：
5.5
通讯作者：
Ying Peng;Kun Li;Rong-juan Pei;Chun-chen Wu;C. Liang;Yun Wang;Xinwen Chen
中科院分区：
文献类型：
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作者：
Ying Peng;Kun Li;Rong-juan Pei;Chun-chen Wu;C. Liang;Yun Wang;Xinwen Chen
鱼精蛋白是一组首先在精子中发现的高碱性蛋白质，其允许DNA比组蛋白更密集的包装，并将导致基因转录的下调[1]。众所周知，苜蓿银纹夜蛾核型多角体病毒（AcMNPV）编码P6.9，这是一种鱼精蛋白样蛋白，通过与病毒基因组结合形成病毒亚核小体[29]。先前的研究表明，P6.9对于病毒核衣壳组装是必不可少的，而它对病毒基因组复制没有影响[31]。在本研究中，P6.9在病毒基因转录调控中的作用的特点。与通常下调基因转录的鱼精蛋白或其他鱼精蛋白样蛋白相比，P6.9似乎在感染后12-24小时（hpi）上调病毒基因转录，而它对于病毒基因转录的基础水平不是必需的。荧光显微镜显示P6.9与DNA的共定位与P6.9对病毒基因转录的影响在时间和空间上是同步的，表明P6.9-DNA缔合有助于转录调控。染色质分级分析进一步揭示了P6.9和宿主RNA聚合酶II在24 hpi时在相同的转录活性染色质组分中的意外共存，这可能有助于病毒基因在感染后期的转录上调。
Protamines are a group of highly basic proteins first discovered in spermatozoon that allow for denser packaging of DNA than histones and will result in down-regulation of gene transcription[1]. It is well recognized that theAutographa californicamulticapsid nucleopolyhedrovirus (AcMNPV) encodes P6.9, a protamine-like protein that forms the viral subnucleosome through binding to the viral genome[29]. Previous research demonstrates that P6.9 is essential for viral nucleocapsid assembly, while it has no influence on viral genome replication[31]. In the present study, the role of P6.9 in viral gene transcription regulation is characterized. In contrast to protamines or other protamine-like proteins that usually down-regulate gene transcription, P6.9 appears to up-regulate viral gene transcription at 12–24 hours post infection (hpi), whereas it is non-essential for the basal level of viral gene transcription. Fluorescence microscopy reveals the P6.9’s co-localization with DNA is temporally and spatially synchronized with P6.9’s impact on viral gene transcription, indicating the P6.9-DNA association contributes to transcription regulation. Chromatin fractionation assay further reveals an unexpected co-existence of P6.9 and host RNA polymerase II in the same transcriptionally active chromatin fraction at 24 hpi, which may probably contribute to viral gene transcription up-regulation in the late infection phase.