Characterization of the subcellular localization of Epstein-Barr virus encoded proteins in live cells

Abstract

Epstein-Barr virus (EBV) is the pathogenic factor of numerous human tumors, yet certain of its encoded proteins have not been studied. As a first step for functional identification, we presented the construction of a library of expression constructs for most of the EBV encoded proteins and an explicit subcellular localization map of 81 proteins encoded by EBV in mammalian cells. Viral open reading frames were fused with enhanced yellow fluorescent protein (EYFP) tag in eukaryotic expression plasmid then expressed in COS-7 live cells, and protein localizations were observed by fluorescence microscopy. As results, 34.57% (28 proteins) of all proteins showed pan-nuclear or subnuclear localization, 39.51% (32 proteins) exhibitted pan-cytoplasmic or subcytoplasmic localization, and 25.93% (21 proteins) were found in both the nucleus and cytoplasm. Interestingly, most envelope proteins presented pan-cytoplasmic or membranous localization, and most capsid proteins displayed enriched or complete localization in the nucleus, indicating that the subcellular localization of specific proteins are associated with their roles during viral replication. Taken together, the subcellular localization map of EBV proteins in live cells may lay the foundation for further illustrating the functions of EBV-encoded genes in human diseases especially in its relevant tumors.

Selectable Marker Gene Removal and Expression of Transgene by Inducible Promoter Containing FFDD Cis-Acting elements in Transgenic Plants

“…The number of H-Bond, Helice, Strand and Turn included in this model were 81, 7, 2, and 16, respectively. confirms again the previous report (33). However, the future study needs to be carried out to determine whether BGLF2 possess similar functions with its homologues.…”

Characterization of the Nucleocytoplasmic Transport Mechanisms of Epstein-Barr Virus BFLF2

“…BFLF2 is a nuclear phosphoprotein of approximately 35 kDa, expressed early during viral replicative cycle, but is not detectable in extracellular virions [16]. Our recent study showed that BFLF2 localizes absolutely to the nucleus [3], which is in accordance with the subcellular localization of HSV-1 UL31 [19,20]. However, the determining mechanisms for its subcellular transport were not well understood, thus prompting us to investigate the nucleocytoplasmic transport mechanisms of BFLF2.…”

“…The BFLF2 open reading frame (ORF) was polymerase chain reaction amplified from BAC DNA of EBV B95-8 strain (174-kb BAC) [3,22], then the product was digested with EcoRI and BamHI and inserted into the green fluorescent protein variant mammalian expression vector pEYFP-N1 (Clontech, BD Biosciences, Palo Alto, CA) encoding enhanced yellow fluorescent protein (EYFP), to creat pBFLF2-EYFP. Fragments and mutants of BFLF2 were inserted into pEYFP-C1 (Clontech, BD Biosciences) to analyze the functions of the predicted NLS and NES.…”

“…EBV is also associated with the development of certain malignancies, including African Burkitt lymphomas, B-cell lymphomas of immunocompromised patients, nasopharyngeal carcinomas, Hodgkin's disease, and occasionally with T-cell lymphomas and gastric cancers [2]. The EBV genome is composed of linear double-stranded DNA, with approximately 172 kilobase pairs in length [3], which encodes about 86 proteins [4]. According to their localization in the virions, the proteins could be divided into five groups: envelope, tegument, capsid, and unclassified and nonstructural proteins.…”

“…According to their localization in the virions, the proteins could be divided into five groups: envelope, tegument, capsid, and unclassified and nonstructural proteins. This complicated network of proteins leads to various consequences on the host cell and guarantees efficient viral proliferation [3].…”