title: Cloning and characterization of an ATBF1 isoform that expresses in a neuronal differentiation-dependent manner.
abstract: The human ATBF1 cDNA reported previously, now termed ATBF1-B, encodes a 306-kDa protein containing 4 homeodomains and 18 zinc fingers including one pseudo zinc finger motif. Here, we report the isolation of a second ATBF1 cDNA, 12 kilobase pairs long, termed ATBF1-A. The deduced ATBF1-A protein is 404 kDa in size and differs from ATBF1-B by a 920-amino acid extention at the N terminus. Analysis of 5'-genomic sequences showed that the 5'-noncoding sequences specific to ATBF1-A and ATBF1-B transcripts were contained in distinct exons that could splice to a downstream exon common to the ATBF1-A and ATBF1-B mRNAs. The expression of ATBF1-A transcripts increased to high levels when P19 and NT2/D1 cells were treated with retinoic acid to induce neuronal differentiation. Preferential expression of ATBF1-A transcripts was also observed in developing mouse brain. Transient transfection assays showed that the 5.5-kilobase pair sequence upstream of the ATBF1-A-specific exon (exon 2) supported expression of the linked chloramphenicol acetyltransferase gene in neuronal cells derived from P19 cells but not in undifferentiated P19 or in F9 cells, which do not differentiate into neurons. These results showed that ATBF1-A and ATBF1-B transcripts are generated by alternative promoter usage combined with alternative splicing and that the ATBF1-A-specific promoter is activated during neuronal differentiation.
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, University of Calgary, Alberta, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Miura
authors.forename: T
authors.initials: T
authors.lastname: Tam
authors.forename: A
authors.initials: A
authors.lastname: Ido
authors.forename: T
authors.initials: T
authors.lastname: Morinaga
authors.forename: T
authors.initials: T
authors.lastname: Miki
authors.forename: T
authors.initials: T
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Tamaoki
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D005091:Exons; D015870:Gene Expression; D018398:Homeodomain Proteins; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012260:Ribonucleases; D016335:Zinc Fingers / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C489511:Zfhx3 protein, mouse; C071660:ZFHX3 protein, human; D012260:Ribonucleases