title: The human high mobility group (HMG)-box transcription factor TCF-1: novel isoforms due to alternative splicing and usage of a new exon IXA.
abstract: The C-terminal peptide sequences of the human lymphocyte-specific high mobility group (HMG)-box transcription factor TCF-1 are determined by alternative splice mechanisms affecting the exons VIII to X. Here we report, in addition to four splice forms described previously (TCF-1A, B, C, D), the identification of three novel transcripts designated TCF-1E, F, G. Cloning and sequencing of the novel cDNAs revealed (i) joining of the exons VIII and IX to an internal exon X splice acceptor site resulting in a new open reading frame (ORF) of 99 amino acids derived from exon X sequences, (ii) the identification of an additional functional splice acceptor site within exon X, and (iii) a new 81-nucleotide insertion between exon VIII and exon X sequences in a novel transcript form. Genomic cloning and sequence analysis of this transcribed segment of 81 basepairs revealed that it was bordered by canonical splice consensus sites and located in a distance of some 400 bp from both the exons IX and X. It was therefore termed exon IXA. Novel ORFs were generated as a consequence of these alternative splice mechanisms resulting in TCF-1 gene products with significantly different C-terminal peptide sequences, which are prone to selective protein-protein interactions or transactivating functions.
authors.affiliation: Institut für Humangenetik der Universität, Erlangen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Mayer
authors.forename: E
authors.initials: E
authors.lastname: Wolff
authors.forename: H
authors.initials: H
authors.lastname: Clevers
authors.forename: W G
authors.initials: WG
authors.lastname: Ballhausen
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D018076:DNA, Complementary / Q000032:analysis / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics*; D005091:Exons; D006609:High Mobility Group Proteins / Q000235:genetics*; D006801:Humans; D051821:Lymphoid Enhancer-Binding Factor 1; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D051822:T Cell Transcription Factor 1; D014157:Transcription Factors / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D012333:RNA, Messenger; D051822:T Cell Transcription Factor 1; C497576:TCF7 protein, human; D014157:Transcription Factors