Defective anion transport and marked spherocytosis with membrane instability caused by hereditary total deficiency of red cell band 3 in cattle due to a nonsense mutation
Defective anion transport and marked spherocytosis with membrane instability caused by hereditary total deficiency of red cell band 3 in cattle due to a nonsense mutation
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DOI：
10.1172/jci118610
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发表时间：
1996-04-15
影响因子：
15.9
通讯作者：
Maede, Y
中科院分区：
文献类型：
--
作者：
Inaba, M;Yawata, A;Maede, Y
我们研究了表现出中度失代偿性贫血、以常染色体不完全显性模式遗传的遗传性球形红细胞增多症和生长迟缓的牛受试者。基于 SDS-PAGE、免疫印迹和冷冻断裂法电镜分析的结果，我们在此表明先证者红细胞完全缺乏带 3 蛋白。先证者带 3 cDNA 和基因组 DNA 的序列分析显示，在与人红细胞带 3 cDNA 中密码子 646 对应的位置处，C --> T 取代导致无义突变（CGA --> TGA；Arg --> Stop）。先证者红细胞缺乏血影蛋白、锚蛋白、肌动蛋白和蛋白质4.2，导致膜骨架网络扭曲和破坏，密度降低。因此，先证者红细胞膜极其不稳定，并以几种不同的方式表现出表面积的损失，例如内陷、囊泡形成和微泡挤出，导致球形红细胞的形成。第 3 条带的完全缺乏还导致 Cl-/HCO3- 交换缺陷，导致轻度酸中毒，同时先证者血液中 HCO3- 浓度和总 CO2 降低。我们的结果表明，带 3 确实有助于红细胞膜稳定性、二氧化碳运输和酸碱稳态，但并不总是对这种哺乳动物的生存至关重要。
We studied bovine subjects that exhibited a moderate uncompensated anemia with hereditary spherocytosis inherited in an autosomal incompletely dominant mode and retarded growth. Based on the results of SDS-PAGE, immunoblotting, and electron microscopic analysis by the freeze fracture method, we show here that the proband red cells lacked the band 3 protein completely. Sequence analysis of the proband band 3 cDNA and genomic DNA showed a C --> T substitution resulting in a nonsense mutation (CGA --> TGA; Arg --> Stop) at the position corresponding to codon 646 in human red cell band 3 cDNA. The proband red cells were deficient in spectrin, ankyrin, actin, and protein 4.2, resulting in a distorted and disrupted membrane skeletal network with decreased density. Therefore, the proband red cell membranes were extremely unstable and showed the loss of surface area in several distinct ways such as invagination, vesiculation, and extrusion of microvesicles, leading to the formation of spherocytes. Total deficiency of band 3 also resulted in defective Cl-/HCO3- exchange, causing mild acidosis with decreases in the HCO3- concentration and total CO2 in the proband blood. Our results demonstrate that band 3 indeed contributes to red cell membrane stability, CO2 transport, and acid-base homeostasis, but is not always essential to the survival of this mammal.