Blumenthal Thomas, Evans Donald, Link Christopher D, Guffanti Alessandro, Lawson Daniel, Thierry-Mieg Jean, Thierry-Mieg Danielle, Chiu Wei Lu, Duke Kyle, Kiraly Moni, Kim Stuart K
Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Box B121, 4200 E. 9th Avenue, Denver, Colorado 80262, USA.
Nature. 2002 Jun 20;417(6891):851-4. doi: 10.1038/nature00831.
The nematode worm Caenorhabditis elegans and its relatives are unique among animals in having operons. Operons are regulated multigene transcription units, in which polycistronic pre-messenger RNA (pre-mRNA coding for multiple peptides) is processed to monocistronic mRNAs. This occurs by 3' end formation and trans-splicing using the specialized SL2 small nuclear ribonucleoprotein particle for downstream mRNAs. Previously, the correlation between downstream location in an operon and SL2 trans-splicing has been strong, but anecdotal. Although only 28 operons have been reported, the complete sequence of the C. elegans genome reveals numerous gene clusters. To determine how many of these clusters represent operons, we probed full-genome microarrays for SL2-containing mRNAs. We found significant enrichment for about 1,200 genes, including most of a group of several hundred genes represented by complementary DNAs that contain SL2 sequence. Analysis of their genomic arrangements indicates that >90% are downstream genes, falling in 790 distinct operons. Our evidence indicates that the genome contains at least 1,000 operons, 2 8 genes long, that contain about 15% of all C. elegans genes. Numerous examples of co-transcription of genes encoding functionally related proteins are evident. Inspection of the operon list should reveal previously unknown functional relationships.
线虫秀丽隐杆线虫及其亲属在动物中独一无二，拥有操纵子。操纵子是受调控的多基因转录单元，其中多顺反子前体信使核糖核酸（编码多种肽的前体信使核糖核酸）被加工成单顺反子信使核糖核酸。这是通过3'端形成和使用专门的SL2小核核糖核蛋白颗粒对下游信使核糖核酸进行反式剪接来实现的。以前，操纵子中基因的下游位置与SL2反式剪接之间的相关性很强，但只是传闻。虽然只报道了28个操纵子，但秀丽隐杆线虫基因组的完整序列揭示了众多基因簇。为了确定这些基因簇中有多少代表操纵子，我们用含有SL2的信使核糖核酸探测全基因组微阵列。我们发现约1200个基因有显著富集，包括一组由含有SL2序列的互补脱氧核糖核酸代表的几百个基因中的大多数。对它们基因组排列的分析表明，超过90%是下游基因，分属于790个不同的操纵子。我们的证据表明，基因组至少含有1000个操纵子，每个操纵子有2至8个基因，包含秀丽隐杆线虫所有基因的约15%。编码功能相关蛋白质的基因共转录的众多例子很明显。检查操纵子列表应该能揭示以前未知的功能关系。
