The two subunits of human molybdopterin synthase: evidence for a bicistronic messenger RNA with overlapping reading frames
The two subunits of human molybdopterin synthase: evidence for a bicistronic messenger RNA with overlapping reading frames
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DOI：
10.1093/nar/27.3.854
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发表时间：
1999-02-01
影响因子：
14.9
通讯作者：
Unkles, SE
中科院分区：
文献类型：
--
作者：
Sloan, J;Kinghorn, JR;Unkles, SE
钼酶是普遍存在的，需要一个辅基称为钼辅因子的活动。我们在这里提供的证据表明，两个异聚亚基（MOCO 1-A和MOCO 1-B）的人类白蝶呤合酶，这是参与前体Z的转化为白蝶呤的钼辅因子生物合成途径，指定由一个单一的双顺反子mRNA重叠的阅读框架。该转录物的丰度低，并显示出可变的组织分布。我们提出，40 S核糖体亚基对MOCO 1-A的第一个翻译起始密码子的漏扫描发生，允许识别下游MOCO 1-B阅读框的AUG。这样的遗传排列可能导致低表达酶亚基的恒定比例和紧密接近，这应该是先验的，特别有利于在复杂的哺乳动物细胞中组装。MOCO 1基因座位于人类5号染色体上。
Molybdoenzymes are ubiquitous and require a prosthetic group called the molybdenum cofactor for activity. We provide evidence here that the two heteromeric subunits (MOCO1-A and MOCO1-B) of human molybdopterin synthase, which is involved in the conversion of precursor Z to molybdopterin in the molybdenum cofactor biosynthetic pathway, are specified by a single bicistronic mRNA with overlapping reading frames. The transcript is in low abundance and shows variable tissue distribution. We propose that leaky scanning of the first translational initiation codon for MOCO1-A by 40S ribosomal subunits occurs, allowing recognition of the AUG for the downstream MOCO1-B reading frame. Such a genetic arrangement may result in a constant ratio and close proximity of lowly expressed enzyme subunits which should, a priori, be especially advantageous for assembly in complex mammalian cells. The MOCO1 locus resides on human chromosome 5.