Macrae M, Plasterk R H, Coffino P
Department of Microbiology and Immunology, University of California, San Francisco 94143, USA.
Genetics. 1995 Jun;140(2):517-25. doi: 10.1093/genetics/140.2.517.
The gene (odc-1) encoding ornithine decarboxylase, a key enzyme in polyamine biosynthesis, was cloned and characterized. Two introns interrupt the coding sequence of the gene. The deduced protein contains 422 amino acids and is homologous to ornithine decarboxylases of other eukaryotic species. In vitro translation of a transcript of the cDNA yielded an enzymatically active product. The mRNA is 1.5 kb in size and is formed by trans-splicing to SL1, a common 5' RNA segment. odc-1 maps to the middle of LG V, between dpy-11 and unc-42 and near a breakpoint of the nDf32 deficiency strain. Enzymatic activity is low in starved stage 1 (L1) larva and, after feeding, rises progressively as the worms develop. Targeted gene disruption was used to create a null allele. Homozygous mutants are normally viable and show no apparent defects, with the exception of a somewhat reduced brood size. In vitro assays for ornithine decarboxylase activity, however, show no detectable enzymatic activity, suggesting that ornithine decarboxylase is dispensible for nematode growth in the laboratory.
编码鸟氨酸脱羧酶（多胺生物合成中的关键酶）的基因（odc-1）被克隆并进行了表征。该基因的编码序列被两个内含子打断。推导的蛋白质含有422个氨基酸，与其他真核生物物种的鸟氨酸脱羧酶同源。cDNA转录本的体外翻译产生了一种具有酶活性的产物。mRNA大小为1.5 kb，通过与常见的5' RNA片段SL1反式剪接形成。odc-1定位于LG V的中间，在dpy-11和unc-42之间，靠近nDf32缺失菌株的一个断点。在饥饿的1期（L1）幼虫中酶活性较低，进食后，随着蠕虫发育酶活性逐渐升高。使用靶向基因破坏创建了一个无效等位基因。纯合突变体通常是可行的，除了产卵量略有减少外没有明显缺陷。然而，鸟氨酸脱羧酶活性的体外测定显示没有可检测到的酶活性，这表明鸟氨酸脱羧酶在实验室条件下线虫生长中是可有可无的。
