Molecular biochemistry and electron microscopy in normal and abnormal human red cell membrane protein 4.2

以下是最近两年（1995-1997）的结果。遗传性溶血性贫血蛋白带4.2 （P4.2）异常(1)完全P4.2缺乏型(1)P4.2基因突变：检测到两个新突变：等位基因小松（523GAT*TAT）和志贺（317CGC*TGC）。电镜观察到两种类型的膜内颗粒和细胞骨架网络有明显的紊乱。(2)蛋白带3 （B3）基因突变：检测到2个新突变；首先，具有Memphis II多态性（K56E+P854L）的等位基因冲绳（G714R）和处于复合杂合状态的等位基因福冈（G130R）。结果表明，这些突变导致P4.2蛋白完全缺失，B3蛋白明显减少。其次，P4.2和B3蛋白联合缺乏症为世界首例。B3基因分析显示C*T核苷酸替换导致密码子646无义突变。(2)部分B3缺乏型以遗传性球形细胞增多症（HS）多见采用PCR/SSCP方法对HS病例B3基因进行分析。在B3基因的第5、12、17和19外显子检测到4个突变。(3) P4.2变异类型采用生物化学和分子生物学方法研究了P4.2双偶体Nagano （72/74kD）的发病机制。在P4.2基因杂合状态的第10外显子1463nt （R488H）处发现了一个新的突变。(1)人成红细胞中的蛋白表达研究表明，红细胞分化过程中膜蛋白的表达始于谱蛋白、糖蛋白和带3，其次是蛋白4.1和锚蛋白，在分化的最后阶段由蛋白4.2的表达完成。(2) P4.2蛋白的生理功能生化和免疫电镜研究表明，P4.2蛋白可能作为一种锚定蛋白，将谱蛋白网络连接到B3蛋白上。少

The following results were obtained for the recent two years (1995-1997)1. Protein band 4.2 (P4.2) anomalies in hereditary hemolyic anemia(1) Complete P4.2 deficiency type(1) P4.2 gene mutations :Two novel mutations were detected : Allele Komatsu (523GAT*TAT) and allele Shiga (317CGC*TGC).Marked derangements were observed on the intramembrane particles and the cytoskeletal network in two types by electron microscopy.(2) Protein band 3 (B3) gene mutations :Two novel mutations were detected ; First, allele Okinawa (G714R) with Memphis II polymorphism (K56E+P854L) and allele Fukuoka (G130R) in compound heterozygous state. It was indicated that these mutations resulted to complete P4.2 protein deficiency with marked decrease of B3 protein.Secondly, a combined deficiency of P4.2 and B3 proteins was described as the first case in the world. The B3 gene analysis showed a C*T nucleotide substitution resulting in a nonsense mutation to codon 646.(2) Partial P4.2 deficiency typeMost cases of thi … More s type were found in hereditary spherocytosis (HS) with partial B3 deficiency.30 HS cases were analyzed on the B3 genes by the method of PCR/SSCP.Four mutations were detected in 5,12,17 and 19th exons of the B3 genes.(3) P4.2 variant typeThe pathogenesis of P4.2 doublet Nagano (72/74kD) was studied by biochemistry and molecular biology.A novel mutation was detected in exon 10 at 1463nt (R488H) of the P4.2 gene in heterozygous state.2. Morphogenesis of red cell membranes(1) Protein expression in human erythroblastsIt was shown that the expression of membrane proteins in erythroid differentiation was initiated in spectrins, glycophorins and band 3, followed by protein 4.1 and ankyrin, and completed by the expression of protein 4.2 at the latest stage of the differentiation.(2) Physiological functions of P4.2 proteinBiochemical and immunoelectron microscopic studies showed the posibility that P4.2 protein might play a role in connecting the spectrin network to B3 protein as a kind of anchoring protein. Less