Polyadenylated transcripts containing random gene fragments are expressed in dinoflagellate mitochondria
Polyadenylated transcripts containing random gene fragments are expressed in dinoflagellate mitochondria
复制标题
DOI：
10.1078/1434-4610-00090
复制
发表时间：
2002-06-01
期刊：
影响因子：
2.5
通讯作者：
Morse, D
中科院分区：
文献类型：
--
作者：
Chaput, H;Wang, YL;Morse, D
从膝沟藻文库中分离到一个富含AT的cDNA，通过序列比较，确定其为线粒体细胞色素氧化酶亚基3（cox3）。与该cox 3探针杂交的转录物是丰富的，在富含poly（A）的RNA组分中发现，并且当通过北方印迹分析测试时具有可变长度。对21个cox 3克隆进行PCR分析，设计分别测量5'和3'末端的长度，表明在3'末端发现长度的最大变异性。3'端的可变长度可能是由于随机位点处的多聚腺苷酸化或由于多聚腺苷酸化信号的严格性降低。对8个cox3 cDNA进行了完全测序，发现在重叠区域中存在多达13个碱基的差异。奇怪的是，最长的cDNA包含甲藻cox 1基因的350个碱基对片段和cox 3序列3'区的细胞色素B（co B）基因的600个碱基对片段。cox3和cob序列的基因片段或多个拷贝在线粒体基因组中可能是丰富的，因为分别使用这些序列作为探针的Southern印迹显示具有几种酶的多个限制性片段。
An AT-rich cDNA isolated from a Gonyaulax library was identified as a putative mitochondrial cytochrome oxidase subunit 3 (cox3) by sequence comparisons. Transcripts hybridizing to this cox3 probe are abundant, are found in poly(A) enriched RNA fractions and have a variable length when tested by Northern blot analysis. A PCR analysis of 21 cox3 clones, designed to measure the length of 5' and 3' ends separately, indicated that the greatest variability in length was found at the 3' end. The variable length of the 3' end may be due to polyadenylation at random sites or to a reduced stringency for polyadenylation signals. Eight cox3 cDNAs were completely sequenced, and were found to differ by up to thirteen bases in the regions of overlap. Curiously, the longest cDNA contained a 350 base pair fragment of a dinoflagellate cox1 gene and a 600 bp fragment of a cytochrome b (cob) gene in the region 3' to the cox3 sequence. Gene fragments or multiple copies of the cox3 and cob sequences may be abundant in the mitochondrial genome since Southern blots, using these sequences separately as probes, show multiple restriction fragments with several enzymes.