CLONING OF A PORTION OF THE CHROMOSOMAL GENE AND CDNA FOR HUMAN BETA-FODRIN, THE NONERYTHROID FORM OF BETA-SPECTRIN

A 96-bp synthetic oligonucleotide corresponding to an amino acid sequence near the N-terminus of erythroid β-spectrin was used to screen a human genomic library, and two overlapping recombinants were isolated. DNA sequence analysis established that the genomic fragment encoded β-fodrin, the nonerythroid form of β-spectrin, by correlation to a known amino acid sequence of human brain β-fodrin. The genomic DNA contained regions that cross-hybridized with an erythroid β-spectrin cDNA probe, and the DNA sequence of these regions revealed a high degree of identity with that of erythroid β-spectrin and a similar exon/intron organization. A single-copy DNA fragment of the β-fodrin genomic clone was used to screen a lymphoid cell cDNA library and two recombinants were isolated. The composite DNA sequence of these various genomic and cDNA clones encoded almost all of the first twelve 106 amino acid repeat segments of β-fodrin that shared 58% identity and 75.5% similarity with the amino acid sequence of β-spectrin and 66% identity with the nucleotide sequence of β-spectrin cDNA. The chromosomal localization of the gene was determined to be chromosome 2 by hybridization of a single-copy probe derived from the cloned genomic DNA to DNA of a panel of somatic hybrid cell lines, and in situ hybridization localized the gene to band 2p21. β-Fodrin was assigned the gene symbol SPTBN1. © 1993 Academic Press. All rights reserved.