Human beta-hexosaminidase alpha chain: coding sequence and homology with the beta chain.
Human beta-hexosaminidase alpha chain: coding sequence and homology with the beta chain.
复制标题
人β-己糖胺酶α链：编码序列以及与β链的同源性。
DOI：
10.1073/pnas.82.23.7830
复制
发表时间：
1985
影响因子：
11.1
通讯作者：
Suzuki,K
中科院分区：
文献类型：
--
作者：
Myerowitz,R;Piekarz,R;Neufeld,EF;Shows,TB;Suzuki,K
我们已经从成人肝脏文库中分离出一个cDNA克隆，p β H α-5，该文库包含β-氨基己糖苷酶α链的整个编码序列。p β H α-5的cDNA插入片段长1944个碱基对，含有168个碱基对的5'非翻译区、186个碱基对的3'非翻译区和对应于529个氨基酸的1587个碱基对的开放阅读框（Mr，60，697）。前17-22个氨基酸满足信号序列的要求。与公开的β链的部分氨基酸序列[O ′ Dowd，B. F.、Quan，F.，Willard，H. F.、Lamhonwah，A. M.，科尔内卢克河G.，洛登，J. A.，格拉韦尔河A. & Mahuran，D. J.（1985）Proc. Natl. Acad. Sci. USA 82，1184-1188]表明这两条链可能是从一个共同的祖先进化而来的。发现较短的α链cDNA与15号染色体的长臂杂交，这是α链基因的已知位置。此外，我们从猴病毒40转化的人成纤维细胞文库中分离出另一个α链cDNA克隆，p β H α-4，该文库在其3'端含有额外的453个碱基对片段。由该额外序列组成的探针仅与培养的人成纤维细胞mRNA制备物中的单个mRNA种类（2.6千碱基）杂交。相比之下，在这些相同的mRNA制备物中，p β H α-5与2.1-脱氢酶主要和2.6-脱氢酶次要mRNA种类杂交，表明存在两种不同的α链mRNA种类，其在3'端不同。一名患有典型泰-萨克斯病的德系犹太人患者的成纤维细胞缺乏两种mRNA，证实了它们的遗传关系。
We have isolated a cDNA clone, p beta H alpha-5, from an adult human liver library that contains the entire coding sequence of the alpha chain of beta-hexosaminidase. The cDNA insert of p beta H alpha-5 is 1944 base pairs long and contains a 168-base-pair 5' untranslated region, a 186-base-pair 3' untranslated region, and an open reading frame of 1587 base pairs corresponding to 529 amino acids (Mr, 60,697). The first 17-22 amino acids satisfy the requirements of a signal sequence. A striking sequence homology with a published partial amino acid sequence for the beta chain [O'Dowd, B. F., Quan, F., Willard, H. F., Lamhonwah, A. M., Korneluk, R. G., Lowden, J. A., Gravel, R. A. & Mahuran, D. J. (1985) Proc. Natl. Acad. Sci. USA 82, 1184-1188] suggests that both chains may have evolved from a common ancestor. A shorter alpha-chain cDNA was found to hybridize to the long arm of chromosome 15, the known location for the alpha-chain gene. In addition, we isolated another alpha-chain cDNA clone, p beta H alpha-4, from a simian virus 40-transformed human fibroblast library that contained an extra 453-base-pair piece at its 3' end. A probe consisting of this additional sequence hybridized exclusively to a single mRNA species (2.6 kilobases) in mRNA preparations from cultured human fibroblasts. In contrast, p beta H alpha-5 hybridized to both a 2.1-kilobase major and a 2.6-kilobase minor mRNA species in these same mRNA preparations, indicating the presence of two distinct alpha-chain mRNA species differing at the 3' end. Fibroblasts from an Ashkenazi Jewish patient with classic Tay-Sachs disease were deficient in both species of mRNA, confirming their genetic relationship.