The complete cDNA and polypeptide sequences of human erythroid alpha-spectrin

• Published in: The Journal of biological chemistry Vol. 265; no. 8; pp. 4434 - 4443
• Main Authors: Sahr, K E, Laurila, P, Kotula, L, Scarpa, A L, Coupal, E, Leto, T L, Linnenbach, A J, Winkelmann, J C, Speicher, D W, Marchesi, V T
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 15.03.1990
• Subjects: Actinin; Amino Acid Sequence; Animals; Base Sequence; Brain - embryology; Brain Chemistry; Carrier Proteins; Chickens; DNA - genetics; Erythrocytes - analysis; erythroid cells; genes; Humans; Liver - analysis; Liver - embryology; Microfilament Proteins; Molecular Sequence Data; Poly A - analysis; Polymorphism, Genetic; Repetitive Sequences, Nucleic Acid; Restriction Mapping; RNA - analysis; RNA, Messenger - analysis; Sequence Homology, Nucleic Acid; Software; Spectrin - genetics
• DOI: 10.1016/S0021-9258(19)39583-3
• ISSN: 0021-9258

Overlapping human erythroid alpha-spectrin cDNA clones were isolated from lambda gt11 libraries constructed from cDNAs of human fetal liver and erythroid bone marrow. The composite 8001-base pair (bp) cDNA nucleotide sequence contains 187-bp 5'- and 528-bp 3'-untranslated regions and has a single long open reading frame of 7287 bp that encodes a polypeptide of 2429 residues. As previously described (Speicher, D. W., and Marchesi, V. T. (1984) Nature 311, 177-180), spectrin is composed largely of homologous 106-amino acid repeat units. From the amino acid sequence deduced from the cDNA, alpha-spectrin can be divided into 22 segments. Segments 1-9 and 12-19 are homologous and can therefore be considered repeats; the average number of identical residues in pairwise comparisons of these repeats is 22 out of 106, or 21%. Of these 17 repeats, 11 are exactly 106 amino acids in length, whereas five others differ from this length by a single residue. Segments 11, 20, and 21, although less homologous, appear to be related to the more highly conserved repeat units. The very N-terminal 22 residues, segment 10, which is atypical both in length and sequence, and the C-terminal 150 residues in segment 22 appear to be unrelated to the conserved repeat units. The sequence of the erythroid alpha-spectrin polypeptide chain is compared to that of human alpha-fodrin and chicken alpha-actinin to which it is related. alpha-Spectrin is more distantly related to dystrophin.