A Control Mechanism of Gene and Protein Expression in Normal and Abnormal Red Cell Membranes

(I)红细胞膜蛋白基因的甲基化状态：通过亚硫酸氢盐法（Zeschnigk M et al.1997）研究了人红细胞膜蛋白（β-血影蛋白、条带3和蛋白4.2）基因启动子区的甲基化状态。正常情况下，外周血单个核细胞带3（B3）基因5 '-CpG-3'的13个位点和蛋白4.2（P4.2）基因的7个CpG位点高度甲基化。相比之下，β-血影蛋白基因的40个位点完全未甲基化。此外，在P4.2完全缺乏的情况下，B3基因的4个CpG位点特异性地未甲基化（亚瓦塔Y等：Blood 90：8b，1997 ; Wada H等：Exp Hematol，出版中，1998）。(II)人类红细胞膜疾病的表型异常：对37例遗传性球形红细胞增多症中的92例和36例正常人的红细胞膜蛋白及其相关基因进行了分析。在这些患者中，在B3基因上鉴定了3个移码突变、5个错义突变和7个多态性，与锚蛋白基因上的12个沉默突变相反（神崎A，等：Brit J Haematol 99：522- 530，1997;神崎A，等：Blood 90：6 b-7 b，1997）。通过免疫电子显微镜在红细胞膜中原位检测到等位基因4.1（-）马德里的明显紊乱的细胞骨架网络（亚瓦塔A等：血液90：2471- 2481，1997）。

(I) The state of methylation on the genes of red cell membrane proteins :The state of methylation was studied at the promoter region of the genes assigned to human red cell membrane proteins (beta-spectrin, band 3, and protein 4.2) by the bisulfite method (Zeschnigk M et al.1997). In normal condition, the 13 sites of 5'-CpG-3' on the genes of band 3 (B3) and the 7 CpG sites of protein 4.2 (P4.2) were heavily methylated in the peripheral mononuclear cells. In contrast, the 40 sites of the beta-spectrin gene were totally unmethylated. In addition, in total deficiency of P4.2, the 4 CpG sites of the B3 gene were specifically unmethylated (Yawata Y,et al : Blood 90 : 8b, 1997 ; Wada H,et al : Exp Hematol, in press, 1998).(II) Phenotypic abnormalities of human red cell membrane disorders :Red cell membrane proteins and their related genes were analyzed in 92 cases of the 37 kindreds of hereditary spherocytosis and in 36 cases of normal subjects. In these patients, 3 frameshift mutations, 5 missense mutations, and 7 polymorphism were identified on the B3 gene, contrary to 12 silent mutations on the ankyrin gene (Kanzaki A,et al : Brit J Haematol 99 : 522-530,1997 ; Kanzaki A,et al : Blood 90 : 6b-7b, 1997). Markedly deranged cytoskeletal network was detected in the red cell membrane in situ with allele 4.1 (-) Madrid by immuno-electron microscopy (Yawata A,et al : Blood 90 : 2471-2481,1997).