Hereditary spherocytosis with spectrin deficiency due to an unstable truncated beta spectrin

A) of the donor consensus splice site of intron 17 leading to an aberrant beta spectrin transcriptional message lacking exons 16 and 17. To elucidate the basis for the decreased amount of the truncated protein on the membrane and the overall spectrin deficiency, we provide evidence that the mutated gene is transcribed but its mRNA is less abundant than its normal counterpart in reticulocytes; we also show that the mutant protein is synthesized in decreased amounts in the cytoplasm of erythroid progenitor cells, and appears to be susceptible to proteolytic degradation. This mutant spectrin underscores the importance of the regulatory role played by the beta spectrin molecule in the assembly of alphabeta spectrin heterodimers on the membrane. -->
ISSN: 1528-0020
0006-4971
DOI: 10.1182/blood.v87.6.2538.bloodjournal8762538
Přístupová URL adresa: https://explore.openaire.eu/search/publication?articleId=doi_________::470dfc71746516996f45f629ed989522
https://doi.org/10.1182/blood.v87.6.2538.bloodjournal8762538
Rights: OPEN
Přírůstkové číslo: edsair.doi...........470dfc71746516996f45f629ed989522
Autor: Jiri Palek, Hani Hassoun, Scott J. Yi, James Murray, J. N. Vassiliadis, Manjit Hanspal, Christine A. Johnson
Rok vydání: 1996
Předmět:
Zdroj: Blood. 87:2538-2545
ISSN: 1528-0020
0006-4971
DOI: 10.1182/blood.v87.6.2538.bloodjournal8762538
Popis: Red cell membrane protein analysis by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and direct quantitation by radioimmunoassay or cytofluorometry defines four distinct subsets of patients with hereditary spherocytosis: Patients with isolated spectrin deficiency, combined spectrin and ankyrin deficiency, band 3 deficiency, and protein 4.2 deficiency. In regard to the first group, only one mutation of beta spectrin has been reported in the literature. We describe a spectrin variant characterized by a truncated beta chain, and associated with hereditary spherocytosis and isolated spectrin deficiency. The clinical phenotype consists of a moderate hemolytic anemia with spherocytosis and frequent spiculation of the red cells. We present the biochemical characteristics of this mutant protein and show that it constitutes only 12% of the total spectrin on the membrane. We show that the truncation of the protein is the result of a single point mutation at position +1 (G-->A) of the donor consensus splice site of intron 17 leading to an aberrant beta spectrin transcriptional message lacking exons 16 and 17. To elucidate the basis for the decreased amount of the truncated protein on the membrane and the overall spectrin deficiency, we provide evidence that the mutated gene is transcribed but its mRNA is less abundant than its normal counterpart in reticulocytes; we also show that the mutant protein is synthesized in decreased amounts in the cytoplasm of erythroid progenitor cells, and appears to be susceptible to proteolytic degradation. This mutant spectrin underscores the importance of the regulatory role played by the beta spectrin molecule in the assembly of alphabeta spectrin heterodimers on the membrane.
Databáze: OpenAIRE
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