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

最近两年（1995-1997年）取得的成果如下：遗传性溶血性贫血P4.2蛋白带异常（1）完全性P4.2缺乏型（1）P4.2基因突变：发现两种新的突变：等位基因Komatsu（523 GAT * 达特）和等位基因滋贺（317 CGC *TGC），电镜下两种类型的细胞膜内颗粒和细胞骨架网络均出现明显的紊乱。(2)蛋白带3（B3）基因突变：检测到两种新突变，一是等位基因冲绳（G714 R）与孟菲斯II多态性（K56 E + P854 L）和等位基因福冈（G130 R）处于复合杂合状态。结果表明，这些突变导致P4.2蛋白完全缺失，B3蛋白显著降低。B3基因分析显示C*T核苷酸取代导致密码子646的无义突变。(2)部分P4.2缺乏型 ...更多信息 应用PCR/SSCP方法对30例遗传性球形红细胞增多症（HS）B3基因进行了分析，发现B3基因第5、12、17和19外显子有4处突变。(3)P4.2变异型采用生物化学和分子生物学方法研究了P4.2双联体Nagano（72/74 kD）的发病机制，发现P4.2基因第10外显子1463 nt（R488 H）杂合突变.红细胞膜的形态发生（1）人成红细胞膜蛋白的表达结果表明，红细胞分化过程中膜蛋白的表达是以血影蛋白、血型糖蛋白和带3蛋白开始的，其次是4.1蛋白和锚蛋白，到分化后期以4.2蛋白的表达完成。(2)P4.2蛋白的生理功能生物化学和免疫电镜研究表明，P4.2蛋白可能作为锚定蛋白参与连接血影蛋白网络和B3蛋白。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