The complete cDNA and polypeptide sequences of human erythroid alpha-spectrin.
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.
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
K E
KE
Sahr
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P
Laurila
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L
Kotula
A L
AL
Scarpa
E
E
Coupal
T L
TL
Leto
A J
AJ
Linnenbach
J C
JC
Winkelmann
D W
DW
Speicher
V T
VT
Marchesi
D000185:Actinin; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000196:embryology; D001923:Brain Chemistry; D002352:Carrier Proteins; D002645:Chickens; D004247:DNA / Q000235:genetics*; D004912:Erythrocytes / Q000032:analysis*; D006801:Humans; D008099:Liver / Q000032:analysis / Q000196:embryology; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D011061:Poly A / Q000032:analysis; D011110:Polymorphism, Genetic; D012313:RNA / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012984:Software; D013049:Spectrin / Q000235:genetics*
D000185:Actinin; D002352:Carrier Proteins; D004247:DNA; D008840:Microfilament Proteins; D011061:Poly A; D012313:RNA; D012333:RNA, Messenger; D013049:Spectrin