Characterization of human brain cDNA encoding the general isoform of beta-spectrin.
The complete primary structure of the general form of human beta-spectrin (beta G) has been deduced from cDNAs isolated from human brain. beta G-Spectrin is encoded by a gene located on human chromosome 2. beta G-Spectrin and erythrocyte beta-spectrin (beta R) share identical domain organization, with sequence identity of 60% and sequence similarity of 77%. beta-Spectrins have closely related N-terminal domains implicated in binding to actin, and 17 copies of a 106-residue repeat motif with consensus residues that are highly conserved between beta-spectrins as well as alpha-spectrins. C-terminal domains of beta G and the 270-kDa beta R-spectrins are candidate regions to associate with alpha-spectrin, and exhibit 75% similarity. beta G- and beta R-spectrins exhibit different patterns of expression in tissues and follow different developmental programs in those tissues where they are co-expressed. beta G-Spectrin is present in all tissues examined except for erythrocytes, while beta R-spectrin could be detected only in erythrocytes, brain, and heart. beta G- and beta R-Spectrins are both expressed in brain, but beta R appeared later in post-natal development and was highly enriched in cerebellum in contrast to the broad regional distribution of beta G-spectrin. beta-Spectrins are likely to perform related but distinct functions, with beta G in a general, constitutive role and beta R-spectrin involved in more specialized activities of differentiated cells.
Hu
R J
RJ
Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Watanabe
M
M
Bennett
V
V
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2; D004247:DNA / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D013049:Spectrin / Q000235:genetics*
D013049:Spectrin; D004247:DNA