title: Cloning and characterization of a novel splicing isoform of USF1.
abstract: The ubiquitous basic helix-loop-helix transcription factor USFs encoded by two distinct genes (USF1 and USF2) recognize a core motif, CACGTG, termed E box and regulate the expression of a variety of genes. USF1 and USF2 proteins form homo- and heterodimers to bind the target core motif DNA. Here, we report the molecular cloning and functional characterization of a novel alternative splicing variant of human USF1 (hUSF1), termed USF1/BD. Compared with USF1 wild-type (wt), USF1/BD lacks the N-terminal transactivation domain. Cloning and characterization of the hUSF1 genomic region revealed that USF1/BD is generated by excising the sequence corresponding to a part of exon 4. In transiently transfected cells, USF1/BD was localized in the nucleus and repressed the promoter activity of the human angiotensinogen gene. In vitro translated USF1/BD possessed DNA binding activity as a homodimer and a heterodimer with USF1 (wt). These results suggest that USF1/BD plays a role as a modulator of USF1 to control the expression of target genes.
authors.affiliation: Institute of Applied Biochemistry, Center for Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan. akif@tara.tsukuba.ac.jp
authors.forename: Tomoko
authors.initials: T
authors.lastname: Saito
authors.forename: Takayuki
authors.initials: T
authors.lastname: Oishi
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Yanai
authors.forename: Yoko
authors.initials: Y
authors.lastname: Shimamoto
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Fukamizu
mesh_terms: D017398:Alternative Splicing; D000808:Angiotensinogen / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018388:Codon, Terminator; D004268:DNA-Binding Proteins; D019281:Dimerization; D024721:E-Box Elements; D005091:Exons; D005786:Gene Expression Regulation; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D051720:Upstream Stimulatory Factors
chemical_list: D018388:Codon, Terminator; D004268:DNA-Binding Proteins; D014157:Transcription Factors; C497181:USF1 protein, human; C497184:USF2 protein, human; D051720:Upstream Stimulatory Factors; C497183:Usf1 protein, mouse; C497186:Usf2 protein, mouse; D000808:Angiotensinogen