title: Identification of a novel Sp1 splice variant as a strong transcriptional activator.
abstract: The transcription factor Sp1 regulates expression of numerous genes involved in many cellular processes. Different post-transcriptional modifications can influence the transcriptional control activity and stability of Sp1. In addition to these modifications, alternative splicing isoforms may also be the basis of its distinct functional activities. In this study, we identified a novel alternative splice isoform of Sp1 named Sp1c. This variant is generated by exclusion of a short domain, which we designate α, through alternative splice acceptor site usage in the exon 3. The existence of this new isoform was confirmed in vivo by Western blotting analysis. Although at very low levels, Sp1c is ubiquitously expressed, as seen in its full-length Sp1. A preliminary characterization of Sp1c shows that: (a) Sp1c works as stronger activator of transcription than full-length Sp1; (b) percentage of HEK293 Sp1c-overexpressing cells is higher in G1 phase and lower in S phase than percentage of HEK293 Sp1-overexpressing cells.
authors.affiliation: Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy.
authors.forename: Vittoria
authors.initials: V
authors.lastname: Infantino
authors.forename: Paolo
authors.initials: P
authors.lastname: Convertini
authors.forename: Francesco
authors.initials: F
authors.lastname: Iacobazzi
authors.forename: Isabella
authors.initials: I
authors.lastname: Pisano
authors.forename: Pasquale
authors.initials: P
authors.lastname: Scarcia
authors.forename: Vito
authors.initials: V
authors.lastname: Iacobazzi
mesh_terms: D017398:Alternative Splicing; D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics; D005091:Exons; D050259:Genes, Mitochondrial; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D020033:Protein Isoforms; D016329:Sp1 Transcription Factor; D015534:Trans-Activators