title: Transcription factor BACH1 is recruited to the nucleus by its novel alternative spliced isoform.
abstract: The transcription factor Bach1 is a member of a novel family of broad complex, tramtrack, bric-a-brac/poxvirus and zinc finger (BTB/POZ) basic region leucine zipper factors. Bach1 forms a heterodimer with MafK, a member of the small Maf protein family (MafF, MafG, and MafK), which recognizes the NF-E2/Maf recognition element, a cis-regulatory motif containing a 12-O-tetradecanoylphorbol-13-acetate-responsive element. Here we describe the gene structure of human BACH1, including a newly identified promoter and an alternatively RNA-spliced truncated form of BACH1, designated BACH1t, abundantly transcribed in human testis. The alternate splicing originated from the usage of a novel exon located 5.6 kilobase pairs downstream of the exon encoding the leucine zipper domain, and produced a protein that contained the conserved BTB/POZ, Cap'n collar, and basic region domains, but lacked the leucine zipper domain essential for NF-E2/Maf recognition element binding. Subcellular localization studies using green fluorescent protein as a reporter showed that full-length BACH1 localized to the cytoplasm, whereas BACH1t accumulated in the nucleus. Interestingly, coexpression of BACH1 and BACH1t demonstrated interaction between the molecules and the induction of nuclear import of BACH1. These results suggested that BACH1t recruits BACH1 to the nucleus through BTB domain-mediated interaction.
authors.affiliation: Department of Pediatrics, School of Medicine and Department of Biology, Faculty of Sciences, Hirosaki University, Hirosaki 036-8563, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kanezaki
authors.forename: T
authors.initials: T
authors.lastname: Toki
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: K
authors.initials: K
authors.lastname: Yomogida
authors.forename: K
authors.initials: K
authors.lastname: Sugiyama
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Igarashi
authors.forename: E
authors.initials: E
authors.lastname: Ito
mesh_terms: D017398:Alternative Splicing; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D015152:Blotting, Northern; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D019281:Dimerization; D005091:Exons; D051856:Fanconi Anemia Complementation Group Proteins; D015723:Gene Library; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D008297:Male; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D013737:Testis / Q000378:metabolism; D014018:Tissue Distribution; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D016335:Zinc Fingers
chemical_list: C102108:BACH1 protein, human; D050976:Basic-Leucine Zipper Transcription Factors; D018076:DNA, Complementary; D051856:Fanconi Anemia Complementation Group Proteins; D008164:Luminescent Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins