Molecular analysis of glycophorin C deficiency in human erythrocytes.
Human erythrocyte glycophorin C plays a functionally important role in maintaining erythrocyte shape and regulating membrane mechanical stability. We report here the characterization of the glycophorins C and D deficiency in erythrocytes of the Leach phenotype. Glycophorin C gene is encoded by 4 exons. Amplification of reticulocyte cDNA from Leach phenotype and normal individuals generated a 140-bp fragment when using primers spanning exons 1 and 2. However, no polymerase chain reaction (PCR) products were detected in the Leach phenotype using primers flanking either exons 1 and 3 or exons 1 and 4, suggesting that the 3' end of the mRNA was missing or altered. Exon 4 also appeared to be missing from Leach genomic DNA, based on both Southern hybridization and PCR. These results indicate that an absence of glycophorin C and glycophorin D in erythrocytes from these Leach phenotype individuals is a consequence of a deletion or marked alteration of exon 3 and exon 4 of their glycophorin C gene. Surprisingly, the mutant gene encodes an mRNA stable enough to be detected in circulating reticulocytes. Although this mRNA could encode an N-terminal fragment of glycophorin C, these protein isoform(s) would not be expressed in the membrane because they lack the transmembrane and cytoplasmic domains.
Winardi
R
R
Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
Reid
M
M
Conboy
J
J
Mohandas
N
N
D001483:Base Sequence; D015139:Blotting, Southern; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000502:physiology*; D006021:Glycophorins / Q000172:deficiency* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods; D012313:RNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D015183:Restriction Mapping; D012156:Reticulocytes / Q000502:physiology
D006021:Glycophorins; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D012313:RNA; D004247:DNA