HCMV receptors, signaling and entry

点击翻译按钮获取中文摘要

PROJECT SUMMARY/ABSTRACT Human cytomegalovirus (HCMV) is the leading infectious cause of birth defects in infants. HCMV can also cause a variety of severe diseases in immunocompromised individuals. Mounting evidence have linked HCMV infections to some cancers, most notably malignant glioma. Major progress has been made during the last decade in understanding the molecular mechanism of viral entry and replication. A variety of host receptors and signaling molecules have been shown to regulate HCMV infection. Recently, we used a CRISPR/Cas9 gene editing based screening strategy to search for cellular proteins that are required for HCMV infection of epithelial cells. We found that silencing the expression of an orphan olfactory receptor, OR14I1, drastically reduced HCMV infection in these cells. Further work showed that OR14I1 interacts with the HCMV Pentamer complex (PC). Together with additional evidence, we confirmed that OR14I1 is an HCMV receptor and may play critical role in defining PC-dependent tropism. Despite the progress of identification of several host receptors for HCMV, there are several critical gaps in our current knowledge of the molecular mechanism of viral entry and subsequent viral life cycle. Specifically, it is unclear how HCMV uses multiple host receptors for entry and how virus subvert host cellular signaling pathways facilitate viral replication and spreading. Our long-term goals are to identify how HCMV uses normal host cellular processes to facilitate viral infection, to elucidate the entry mechanism related to viral tropism, define the entry signaling pathways, and trafficking of HCMV to the nucleus by clarifying the roles of OR14I1 and other receptors associated with its broad tropism and pathogenesis. Building on the past work of our group and others, we propose to conduct research on three Specific Aims to address these goal: (1) To elucidate the signaling pathways activated by HCMV-OR14I1 binding and their roles in virus infection and uncover the role OR14I1 plays in cell-cell spread and trafficking; (2) To determine the contribution of different HCMV PC receptors to infection and tropism; and (3) determine the structure of HCMV PC-OR14I1 and determine relevant molecular interactions. Collectively, our proposed research will broadly impact the field by characterizing the essential roles that host receptors, in particular, OR14I1, play in promoting viral entry, replication, and spreading. These studies will have the potential to uncover novel molecular mechanisms underlying HCMV infection, and molecular targets for HCMV therapy.