title: The Sp1 transcription factor does not directly interact with the HIV-1 Tat protein.
abstract: The role of Sp1 in regulating the trans-activating activity of the human immunodeficiency virus type 1 (HIV-1) Tat protein has not yet been clearly defined. In fact, studies on the physical and functional interaction between Sp1 and Tat have yielded contradictory results. Here we investigated whether a physical interaction between Sp1 and Tat indeed occurs, exploiting both biochemical and genetic techniques that allow detection of direct protein-protein interactions. Studies performed with the yeast two-hybrid system indicate that Sp1 does not directly interact with the HIV-1 Tat protein. Control experiments demonstrated that both proteins are functionally expressed in the yeast cells. In vitro binding assays further confirmed that Sp1 does not physically bind Tat. These data suggest that in vivo Tat and Sp1 most likely take part of a multicomponent complex and thus encourage the search of the molecule(s) which mediate Tat-Sp1 interaction.
authors.affiliation: Department of Histology, Microbiology and Medical Biotechnologies, University of Padova, Padova, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Loregian
authors.forename: Katia
authors.initials: K
authors.lastname: Bortolozzo
authors.forename: Silvia
authors.initials: S
authors.lastname: Boso
authors.forename: Barbara
authors.initials: B
authors.lastname: Sapino
authors.forename: Monica
authors.initials: M
authors.lastname: Betti
authors.forename: Maria A
authors.initials: MA
authors.lastname: Biasolo
authors.forename: Antonella
authors.initials: A
authors.lastname: Caputo
authors.forename: Giorgio
authors.initials: G
authors.lastname: Palú
mesh_terms: D000327:Adsorption; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D015696:Gene Products, tat / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015696:Gene Products, tat; D016329:Sp1 Transcription Factor; D054322:tat Gene Products, Human Immunodeficiency Virus