Molecular and Biochemical Studies on Compensatory Mechanisms for Total Band 3 Deficiency in Japanese Black Cattle

第三组已经被认为是哺乳动物生存的必要条件。本研究项目的目标是在Cattle.1）揭示了由PCR-RFLP coinhered的红细胞形态的红细胞形态类型的HS和带3 deficiency确定的基因型的关联分析，该分析结果显示了R664 X突变。R664 X突变是与HS.2相关的主要分子原因的证明。关于红细胞膜蛋白的广泛研究表明，其主要的近似原因是同源细胞和异细胞膜不稳定性出现在波段3-ankyrin-spectrin关联的损失，并减少光谱，相应地。在正常和突变RNA中加入Xenopus oocytes的突变mRNA共注射的定量，以及正常和突变弯曲的体外合成/免疫抑制3演示体内表达的突变蛋白的显性阴性效应。受影响动物体内HS病理学的可能性： （1）第3级-等离子体膜骨架的独立组装。（2）减少正常波段3-ankyrin及其与光谱学之间增强相互作用的关联，在异色屏障和骨骼之间，但不均匀红色细胞中，3） Bovine红细胞具有全波段3 deficiency，由AE 2介导的阴离子传输活动的基础特性，具有敏感性到静态干扰，其中远低于正常细胞中的那些。T e rapid anion exchange was not compensated at all， indicating that the function of？3 is not obligatory to 0イイD22イエD2/C0イD22イエD2 exchange。

Band 3 has been believed to be essential to survival of mammals. The aim of this research project is to define compensatory mechanisms for total band 3 deficiency in cattle.1) Linkage analyses showed that the genotype for R664X mutation determined by PCR-RFLP coinherited with the red cell phenotype of dominantly inherited HS and band 3 deficiency, demonstrating that R664X mutation is the principal molecular cause for dominant hereditary band 3 deficiency in cattle associated with HS.2) Extensive studies on the red cell membrane proteins demonstrated that the major proximal causes for the membrane instability of homozygous and heterozygous cells appear to be the loss of band 3-ankyrin-spectrin association, and the reduction of spectrin, respectively. Quantitation of mutant mRNA co-injection of normal and mutant RNA into Xenopus oocytes, and in vitro synthesis/immunoprecipitation of normal and the mutant bend 3 demonstrated a dominant-negative effect of the mutant protein in vivo on the expression of normal band 3. A hypothetical possibility for pathogenesis of HS in the affected animals involves : (1) Band 3-independent assembly of membrane skeleton to the plasma membrane. (2) Translocation of reduced normal band 3-ankyrin and their association with spectrin to strengthen interactions between the lipid bilayer and the skeleton in heterozygous but not m homozygous red cells.3) Bovine red cells with total band 3 deficiency possessed anion transport activity mediated by AE2, with substrate specificity an sensitivity to stilbene disulfonate which were extremely lower than those in normal cells. T e rapid anion exchange was not compensated at all, indicating that the function of band 3 is not obligatory to 0ィイD22ィエD2/C0ィイD22ィエD2 exchange.