Viswanathan Priya, Venkaiah Betapudi, Kumar M Senthil, Rasheedi Sheeba, Vrati Sudhanshu, Bashyam Murali D, Hasnain Seyed E
Laboratory of Molecular and Cellular Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500076, India.
J Biol Chem. 2003 Dec 26;278(52):52564-71. doi: 10.1074/jbc.M309351200. Epub 2003 Oct 21.
The Autographa californica multinucleocapsid polyhedrosis virus homologous region sequence hr1 enhances transcription from the viral polyhedrin promoter in Spodoptera frugiperda insect cells and independently functions as an origin of replication (ori) sequence. The binding of the host nuclear protein, hr1-binding protein (hr1-BP), is crucial for the enhancer activity (Habib, S., Pandey, S., Chatterji, U., Burma, S., Ahmad, R., Jain, A., and Hasnain, S. E. (1996) DNA Cell Biol. 15, 737-747 and Habib, S., and Hasnain, S. E. (1996) J. Biol. Chem. 271, 28250-28258). We demonstrate that hr1 can also enhance transcription from non-baculoviral promoters like cytomegalovirus and hsp70 in mammalian cells but does not support ori activity in these cells. Unlike insect cells, hr1 can also function in mammalian cells as an enhancer when present in trans. hr1 DNA sequence binds with high affinity and specificity to nuclear factors in the mammalian cells. The insect hr1-BP- and the hr1-BP-like proteins from mammalian cells (mhr1-BP) have different properties with respect to ion requirements, DNA groove binding, and molecular size. When mammalian cells are infected with a recombinant baculovirus containing two promoters, the baculovirus polyhedrin and Drosophila hsp70 gene promoter, the hsp70 gene promoter alone is active in these cells, and this activity is further enhanced by the presence of an additional hr1 in the recombinant virus. hr1 may thus also have a role in baculovirus-mediated gene delivery in mammalian cells.
苜蓿银纹夜蛾多核衣壳多角体病毒同源区域序列hr1可增强草地贪夜蛾昆虫细胞中病毒多角体蛋白启动子的转录，并独立发挥复制起点（ori）序列的功能。宿主核蛋白hr1结合蛋白（hr1-BP）的结合对增强子活性至关重要（哈比卜，S.，潘迪，S.，查特吉，U.，缅甸，S.，艾哈迈德，R.，贾因，A.，和哈桑奈恩，S.E.（1996年）《DNA细胞生物学》15卷，737 - 747页；哈比卜，S.，和哈桑奈恩，S.E.（1996年）《生物化学杂志》271卷，28250 - 28258页）。我们证明，hr1在哺乳动物细胞中也能增强来自非杆状病毒启动子（如巨细胞病毒和hsp70）的转录，但在这些细胞中不支持ori活性。与昆虫细胞不同，hr1在反式存在时也能在哺乳动物细胞中作为增强子发挥作用。hr1 DNA序列与哺乳动物细胞中的核因子具有高亲和力和特异性结合。昆虫hr1-BP和来自哺乳动物细胞的hr1-BP样蛋白（mhr1-BP）在离子需求、DNA沟槽结合和分子大小方面具有不同特性。当哺乳动物细胞被含有两个启动子（杆状病毒多角体蛋白和果蝇hsp70基因启动子）的重组杆状病毒感染时，单独的hsp70基因启动子在这些细胞中具有活性，并且重组病毒中额外的hr1会进一步增强这种活性。因此，hr1在杆状病毒介导的哺乳动物细胞基因递送中可能也发挥作用。
