title: Biochemical characterization of Sf9 Sp-family-like protein factors reveals interesting features.
abstract: We earlier documented the involvement of novel Sp-family-like protein factors in transcription from the Autographa californica nucleopolyhedrovirus (AcNPV) polyhedrin (polh) gene promoter [Ramachandran et al. (2001) J. Biol. Chem. 276: 23440-23449]. These zinc-dependent Sp-like factors bind to two putative Sp-factor-binding motifs, present within the AcSp sequence upstream of the polh promoter, with very high affinity (K(d) = 2.1 x 10(-12) M). Like other polh-promoter-associated host transcription factors, these Sp-like factors display tolerance to high ion concentrations up to even 3 M NaCl. An electrophoretic mobility shift assay demonstrated a probable cross-talk between the Spodoptera frugiperda (Sf9) Sp-family-like proteins and the TFIID complex. In complementary experiments, specific replacements of the Sp-factor-binding motifs with TATA-like elements resulted in expression of a luciferase reporter gene to almost the same level as that obtained with a wild-type native construct. Our results point to the possibility of the involvement of TFIID and Sf9 Sp protein interaction in transcription from the baculovirus polyhedrin promoter.
authors.affiliation: Laboratory of Molecular and Cellular Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.
authors.forename: S
authors.initials: S
authors.lastname: Rasheedi
authors.forename: A
authors.initials: A
authors.lastname: Ramachandran
authors.forename: N Z
authors.initials: NZ
authors.lastname: Ehtesham
authors.forename: S E
authors.initials: SE
authors.lastname: Hasnain
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002457:Cell Extracts / Q000032:analysis; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D024202:Electrophoretic Mobility Shift Assay; D017930:Genes, Reporter; D005814:Genes, Viral; D005822:Genetic Vectors; D019476:Insect Proteins; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D000077183:Occlusion Body Matrix Proteins; D010957:Plasmids; D011485:Protein Binding; D012965:Sodium Chloride / Q000494:pharmacology; D016329:Sp1 Transcription Factor / Q000502:physiology*; D018411:Spodoptera / Q000166:cytology / Q000378:metabolism / Q000821:virology*; D014466:Ultraviolet Rays; D014764:Viral Proteins / Q000235:genetics*; D015678:Viral Structural Proteins / Q000378:metabolism
chemical_list: D002457:Cell Extracts; D003432:Cross-Linking Reagents; D004279:DNA, Viral; D019476:Insect Proteins; D009687:Nuclear Proteins; D000077183:Occlusion Body Matrix Proteins; D016329:Sp1 Transcription Factor; D014764:Viral Proteins; D015678:Viral Structural Proteins; C009829:polyhedrin protein, Nucleopolyhedrovirus; D012965:Sodium Chloride; D008156:Luciferases