Department of Immunobiology, University of Arizona, Tucson, Arizona, USA.
J Virol. 2012 Aug;86(16):8653-62. doi: 10.1128/JVI.00465-12. Epub 2012 Jun 6.
We previously described a novel genetic locus within the ULb' region of the human cytomegalovirus (HCMV) genome that, while dispensable for replication in fibroblasts, suppresses replication in hematopoietic progenitors and augments replication in endothelial cells. This locus, referred to as the UL133-UL138 locus, encodes four proteins, pUL133, pUL135, pUL136, and pUL138. In this work, we have mapped the interactions among these proteins. An analysis of all pairwise interactions during transient expression revealed a robust interaction between pUL133 and pUL138. Potential interactions between pUL136 and both pUL133 and pUL138 were also revealed. In addition, each of the UL133-UL138 locus proteins self-associated, suggesting a potential to form higher-order homomeric complexes. As both pUL133 and pUL138 function in promoting viral latency in CD34(+) hematopoietic progenitor cells (HPCs) infected in vitro, we further focused on this interaction. pUL133 and pUL138 are the predominant complex detected when all proteins are expressed together and require no other proteins in the locus for their association. During infection, the interaction between pUL133 and pUL138 or pUL136 can be detected. A recombinant virus that fails to express both pUL133 and pUL138 exhibited a latency phenotype similar to that of viruses that fail to express either pUL133 or pUL138, indicating that these proteins function cooperatively in latency and do not have independent functions that additively contribute to HCMV latency. These studies identify protein interactions among proteins encoded by the UL133-UL138 locus and demonstrate an important interaction impacting the outcome of HCMV infection.
我们之前描述了人巨细胞病毒 (HCMV) 基因组 ULb' 区域内的一个新的遗传位点，该位点虽然对成纤维细胞的复制是可有可无的，但能抑制造血祖细胞中的复制并增强内皮细胞中的复制。这个位点被称为 UL133-UL138 位点，它编码四个蛋白，pUL133、pUL135、pUL136 和 pUL138。在这项工作中，我们已经确定了这些蛋白之间的相互作用。在瞬时表达过程中对所有两两相互作用的分析表明，pUL133 和 pUL138 之间存在很强的相互作用。还揭示了 pUL136 与 pUL133 和 pUL138 之间潜在的相互作用。此外，UL133-UL138 位点的每个蛋白都能自我关联，这表明它们有可能形成更高阶的同源复合物。由于 pUL133 和 pUL138 都能在体外感染的 CD34+造血祖细胞 (HPC) 中促进病毒潜伏，因此我们进一步关注了这种相互作用。当所有蛋白一起表达时，检测到的主要复合物是 pUL133 和 pUL138，它们的结合不需要该位点中的其他蛋白。在感染过程中，可以检测到 pUL133 和 pUL138 或 pUL136 之间的相互作用。一种不能表达 pUL133 和 pUL138 的重组病毒表现出与不能表达 pUL133 或 pUL138 的病毒相似的潜伏表型，这表明这些蛋白在潜伏中协同作用，并且它们的功能不是独立的，不能累加促进 HCMV 潜伏。这些研究确定了 UL133-UL138 位点编码的蛋白之间的蛋白相互作用，并证明了一个重要的相互作用影响 HCMV 感染的结果。
