Erythroenzymopathies: Mechanisms of isozyme switches and clarification of genetic abnormalities

对不明原因的非球形溶血性贫血患者进行调查后，发现7例新发葡萄糖6-磷酸脱氢酶缺乏症和3例新发丙酮酸激酶(PK)缺乏症。除了这些工作外，我们还可以克隆肝型PK的cDNA，并确定其染色体位置，作为阐明分子异常的第一步。PK有四种同工酶(L、R和lt；M_1和gt；、&lt；M2和gt；)，它们主要由两个不同的基因编码。我们用大鼠肝脏(L)型PK基因探针从日本成人肝脏文库中克隆了一个cDNA克隆。对克隆hlPK-1进行了序列分析，与大鼠PK cDNA序列比较表明，hlPK-1编码人L型PK羧基末端105个氨基酸和一个734个核苷酸的3‘非翻译区。此外，对几个人-鼠杂交细胞的核型分析和与h1PK-1杂交的DNA的Southern杂交分析表明，人L类型的PK基因位于1号染色体上。

We discovered 7 new cases of glucose 6-phosphate dehydrogenase deficiency and 3 new cased of pyruvate kinase (PK) deficiency after the survey of patients showing non-spherocytic hemolytic anemia due to unknown causes. In addition to these works, we could clone the cDNA for liver-type PK and assign its chromosomal locus as a first step for the clarification of molecular anomalies. PK has four isozymes (L, R, <M_1> , <M_2> ) that are encoded mainly by two different genes. We isolated a cDNA clone from a Japanese adult liver <lambda> gt10 cDNA library by using a rat liver (L)-type PK cDNA probe. One positively hybridizing clone, hlPK-1, which contained a 1,049-base pair cDNA insert, was subjected to DNA sequence analysis.Comparisons of the sequence data with the rat PK cDNAs indicated that the cDNA encoded information for the carboxyl terminal 105 amino acids of a human L-type PK and a 3'untranslated region of 734 nucleotides. Furthermore, the karyotype analysis of several human-mouse hybrid cells and Southern blot analysis of DNAs of the hybrids with a hlPK-1 indicated that the human L-type PK gene is located on chromosome 1.