title: Sf-PHB2, a new transcription factor, drives WSSV Ie1 gene expression via a 12-bp DNA element.
abstract: BACKGROUND
  The WSSV immediate early gene ie1 is highly expressed throughout viral infection cycle and may play a central role in initiating viral replication during infection.
  
  
  RESULTS
  Here, a detailed characterization of the ie1 promoter was performed using deletion and mutation analyses to elucidate the role of the individual promoter motifs. Three results were obtained: 1) the ie1 promoter is a classical eukaryotic promoter that contains the initiator element (Inr) and TATA box responsible for the basal promoter activity; 2) mutation or truncation of a predicted Sp1 site decreased the level of promoter activity by about 3-fold, indicating that the Sp1 site is an important cis-element of the promoter; and 3) truncation of a 12-bp sequence that resides at -78/-67 of the ie1 promoter decreased the level of promoter activity by about 14-fold, indicating that the 12-bp motif is a critical upstream element of the ie1 promoter for binding of a strong transcription factor to drive the ie1 gene expression in the cells. Further, the 12-bp DNA binding protein was purified from the nuclear proteins of Sf9 cells using DNA affinity chromatography, and was identified as a homologue of the prohibitin2 protein (named as Sf-PHB2) using mass spectrometry. Furthermore, the DNA binding activity of Sf-PHB2 was verified using a super shift analysis.
  
  
  CONCLUSIONS
  These results support that the Sf-PHB2 is a novel transcription factor that drives WSSV ie1 gene expression by binding to the 12-bp DNA element.
authors.affiliation: Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Harbin, 150001, PR China.
authors.forename: Guoda
authors.initials: G
authors.lastname: Ma
authors.forename: Li
authors.initials: L
authors.lastname: Yu
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Yudong
authors.initials: Y
authors.lastname: Cui
authors.forename: Jimmy
authors.initials: J
authors.lastname: Kwang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D019143:Evolution, Molecular; D015967:Gene Expression Regulation, Viral; D017781:Genes, Immediate-Early; D008969:Molecular Sequence Data; D059372:Nucleotide Motifs; D010802:Phylogeny; D000091402:Prohibitins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D021381:Protein Transport; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D024363:Transcription Initiation Site; D015533:Transcriptional Activation; D046848:White spot syndrome virus 1 / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000091402:Prohibitins; D012097:Repressor Proteins; D014157:Transcription Factors