Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
Virology. 2012 Apr 25;426(1):51-9. doi: 10.1016/j.virol.2012.01.015. Epub 2012 Feb 8.
The influenza polymerase complex composed of PA, PB1 and PB2, plays a key role in viral replication and pathogenicity. Newly synthesized components must be translocated to the nucleus, where replication and transcription of viral genomes take place. Previous studies suggest that while PB2 is translocated to the nucleus independently, PA and PB1 subunits could not localize to the nucleus unless in a PA-PB1 complex. To further determine the molecular interactions between the components, we created a panel of 16 hybridoma cell lines, which produce monoclonal antibodies (mAbs) against each polymerase component. We showed that, although PB1 interacts with both PA and PB2 individually, nuclear localization of PB1 is enhanced only when co-expressed with PA. Interestingly, one of the anti-PA mAbs reacted much more strongly with PA when co-expressed with PB1. These results suggest that PA-PB1 interactions induce a conformational change in PA, which could be required for its nuclear translocation.
流感聚合酶复合物由 PA、PB1 和 PB2 组成，在病毒复制和致病性方面发挥着关键作用。新合成的成分必须易位到细胞核，病毒基因组的复制和转录就在那里进行。先前的研究表明，虽然 PB2 可以独立易位到细胞核，但 PA 和 PB1 亚基不能定位到细胞核，除非形成 PA-PB1 复合物。为了进一步确定各成分之间的分子相互作用，我们创建了一个由 16 个杂交瘤细胞系组成的小组，这些细胞系产生针对每种聚合酶成分的单克隆抗体 (mAb)。我们表明，尽管 PB1 可以与 PA 和 PB2 单独相互作用，但只有与 PA 共表达时，PB1 的核定位才会增强。有趣的是，其中一种抗 PA mAb 与 PB1 共表达时与 PA 的反应要强得多。这些结果表明，PA-PB1 相互作用诱导 PA 发生构象变化，这可能是其核易位所必需的。
