title: Genomic structure of the locus encoding protein 4.1. Structural basis for complex combinational patterns of tissue-specific alternative RNA splicing.
abstract: Protein 4.1 (P4.1) is a multifunctional protein with heterogeneity in molecular weight, intracellular localization, tissue- and development-specific expression patterns. We have analyzed the genomic structure of the locus encoding mouse P4.1 and have systematically analyzed diverse P4.1 mRNA isoforms expressed in erythroid and nonerythroid tissues. Our results indicate that the mouse protein 4.1 gene, over 90 kilobases long, comprises at least 23 exons (13 constitutive exons, 10 alternative exons) interrupted by 22 introns. The donor and acceptor splice site sequences match the consensus sequences for the exon-intron boundaries of most eukaryotic genes. No significant sequence difference was observed between splice junctions of alternative and constitutive exons. Apparently, most alternative exon-encoded peptides are located within particular functional domains of the P4.1 protein: two peptides encoded by alternative exons 4 and 5 are located near or within the glycophorin/calmodulin binding domain, whereas three other alternative exon-encoded peptides (19-amino acid encoded by exon 14, 14-amino acid encoded by exon 15, and 21-amino acid encoded by exon 16) are located near or within the spectrin-actin binding domain. Selective use of exon 2', which carries an upstream translation initiation codon (AUG), may produce an elongated P4.1 isoform (135 kDa) that is predominantly expressed in nonerythroid tissues. Combinatorial splicing of these exons may generate different isoforms that exhibit complicated tissue-specific expression patterns.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China.
authors.forename: J P
authors.initials: JP
authors.lastname: Huang
authors.forename: C J
authors.initials: CJ
authors.lastname: Tang
authors.forename: G H
authors.initials: GH
authors.lastname: Kou
authors.forename: V T
authors.initials: VT
authors.lastname: Marchesi
authors.forename: E J
authors.initials: EJ
authors.lastname: Benz
authors.forename: T K
authors.initials: TK
authors.lastname: Tang
mesh_terms: D016475:3T3 Cells; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001853:Bone Marrow / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D003598:Cytoskeletal Proteins; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D004622:Embryo, Mammalian; D004730:Endothelium, Vascular / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism; D005091:Exons; D015723:Gene Library; D016678:Genome; D006801:Humans; D007438:Introns; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009479:Neuropeptides; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; D009928:Organ Specificity; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping
chemical_list: D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009479:Neuropeptides; D009838:Oligodeoxyribonucleotides; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; C028841:erythrocyte membrane band 4.1 protein; C120557:erythrocyte membrane protein band 4.1-like 1; D004247:DNA