Biochemical and molecular characterization of hereditary myeloperoxidase deficiency
Biochemical and molecular characterization of hereditary myeloperoxidase deficiency
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DOI：
10.1182/blood.v90.10.4126
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发表时间：
1997-11-15
期刊：
影响因子：
20.3
通讯作者：
Baralle, FE
中科院分区：
文献类型：
--
作者：
Romano, M;Dri, P;Baralle, FE
遗传性髓过氧化物酶（MPO）缺乏症是一种中性粒细胞疾病的特点是缺乏过氧化物酶活性。细胞化学，生物化学，光谱，免疫细胞化学和遗传学研究进行了5岁的MPO缺陷的主题和她的父母。父亲也是NPO缺乏，而母亲有24%的正常MPO活性。虽然MPO的典型吸收光谱在父亲和女儿中均不存在，但父亲的中性粒细胞，而不是女儿的中性粒细胞，含有与MPO抗原相关的物质。在父亲的MPO基因中，发现了两个突变，每个突变位于不同的等位基因：T -> C转换，导致非保守性替换M251 T和外显子9内的14个碱基缺失。M251 T取代发生在血红素口袋中所含轻链的羧基末端区域。女儿从父亲那里继承了14个碱基的缺失。对粒细胞前体液体培养物中存在的MPO mRNA的研究令人惊讶地表明，相同的遗传缺陷，即14个碱基缺失，似乎在父亲和女儿中表现出不同的mRMA表型。事实上，来自14个碱基缺失的等位基因的mRNA在父亲中没有发现，并且在女儿中发现了外显子9的77个碱基缺失的异常剪接的MPO mRNA，其包括14个碱基缺失并导致过早终止密码子的产生。Delta 77 mRNA可能来自与Delta 14等位基因相关的其他突变的可能性被排除，因为在该区域（外显子和外显子-内含子连接处）没有发现序列差异。我们的数据表明，由14个碱基的缺失引起的mRNA上下文的改变为mRNA加工中的77个碱基的缺失提供了基础。由于来自父亲的液体培养物的粒细胞前体比来自女儿的粒细胞前体更分化，因此在父亲和女儿中观察到的14个碱基缺失的等位基因的不同行为可能是改变的剪接mRNA的分化阶段依赖性控制的结果，其在分化的早期阶段可以耐受，但在后期阶段降解。在女儿细胞的液体培养物中，除了77个碱基缺失的mRNA外，还发现了野生型序列的mRNA，该mRNA是从母亲遗传的，因为在她的MPO cDNA和MPO基因中没有发现突变。MPO缺陷可能是由一个调控突变引起的，该突变诱导MPO基因在粒细胞分化的早期关闭。(C)1997年，美国血液学会。
Hereditary myeloperoxidase (MPO) deficiency is a neutrophil disorder characterized by the lack of peroxidase activity. Cytochemical, biochemical, spectroscopic, immunocytochemical, and genetic studies were carried out on a fi-year-old MPO-deficient subject and on her parents. The father was also NPO-deficient, whereas the mother had 24% of normal MPO activity. Although the typical absorption spectrum of MPO was absent in both the father and daughter, the father's neutrophils, and not those of the daughter, contained material antigenically related to MPO. In the MPO gene of the father, two mutations were found, each located in a different allele: a T --> C transition, causing the nonconservative replacement M251T and a 14-base deletion within exon 9. The M251T substitution occurred in the carboxy-terminal region of the light chain that is included in the heme pocket. The daughter inherited the 14-base deletion from her father. The study of the MPO mRNAs present in liquid cultures of granulocyte precursors surprisingly showed that the same genetic defect, ie, the 14-base deletion, seemed to exhibit different mRMA phenotypes in the father and the daughter. In fact, mRNA derived from the 14-base-deleted allele was not found in the father and an aberrantly spliced MPO mRNA with a 77-base deletion of exon 9, which includes the 14-base deletion and leads to the generation of a premature stop codon, was found in the daughter. The possibility that Delta 77 mRNA could derive from other mutations linked to the Delta 14 allele was dismissed because no sequence differences were found in the region (exons and exon-intron junctions). Our data indicate that the alteration of the mRNA context caused by the 14-base deletion provide a basis for the 77-base deletion in the mRNA processing. Since the granulocyte precursors from the liquid cultures of the father were more differentiated than those from the daughter, the observed different behavior of the 14-base-deleted allele in the father and daughter may be the result of a differentiation-stage dependent control of altered spliced mRNA, which may be tolerated during the early stages of differentiation but degraded at later stages. In the liquid cultures of the daughter's cells, in addition to the mRNA with the 77-base deletion, a mRNA with the wild type sequence was also found. This mRNA was inherited from the mother, since no mutations were found in her MPO cDNA and MPO gene. The MPO defect might be caused by a regulatory mutation that induces the MPO gene switch off at an early stage of granulocyte differentiation. (C) 1997 by The American Society of Hematology.