title: Identification of a novel nuclear localization signal of baculovirus late expression factor 11.
abstract: The baculovirus late expression factor 11 (LEF-11) has been reported to be involved in viral DNA replication and late/very late gene activation. In this study, serial N- and C-terminal truncations of Bombyx mori nucleopolyhedrovirus (BmNPV) LEF-11 protein were fused with DsRed to investigate the nuclear localization signal by which LEF-11 enters the nucleus. Results show that 72-101 residues at the C-terminus are essential for BmNPV LEF-11 nuclear localization. Sequence alignment of this NLS from multiple LEF-11 homologs revealed high conservation in general. Site-directed mutation analysis showed that five basic residue clusters, namely, K(75)/R(76), H(81), K(83)/R(84), R(87) and K(100), were critical for the nuclear localization of BmNPV LEF-11. Co-IP analysis shows that LEF-11 binds directly to host importin α-3. Immunofluorescence analysis demonstrated that LEF-11 co-localizes with the immediate-early protein IE-1 at viral DNA replication sites in the nucleus. Further BiFC assays demonstrated the interaction of LEF-11 with LEF-3 and LEF-11 itself in the nucleus. Together, these results reveal a previous unknown mechanism for nuclear translocation of baculovirus LEF-11.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Zhan-Qi
authors.initials: ZQ
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China; Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Chun-Dong
authors.initials: CD
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: He
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Ming-Ya
authors.initials: MY
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Hai-Qin
authors.initials: HQ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China.
authors.forename: Wen-Fu
authors.initials: WF
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China. Electronic address: lucheng@swu.edu.cn.
authors.forename: Cheng
authors.initials: C
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Institute of Sericulture and Systems, Southwest University, Chongqing 400715, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China. Electronic address: pmh0476@hotmail.com.
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Pan
mesh_terms: D000818:Animals; D016367:Baculoviridae; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D004252:DNA Mutational Analysis; D017930:Genes, Reporter; D008856:Microscopy, Fluorescence; D019913:Nuclear Localization Signals; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D017384:Sequence Deletion; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D019913:Nuclear Localization Signals; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins
keywords: Bombyx mori; Importin subunit α-3; Nuclear localization signal; Nucleopolyhedrovirus; Protein–protein interaction; Viral DNA replication site