Delseny M, Raynal M, Laudié M, Varoquaux F, Comella P, Wu H J, Cooke R, Grellet F
Physiologie et Biologie Moléculaire des Plantes, CNRS Unite 565, University of Perpignan, France.
Symp Soc Exp Biol. 1996;50:5-9.
Arabidopsis is a crucifer weed with a small genome of about 120 Mbp which has been chosen as a model species for plant molecular genetics. Four years ago, a consortium of nine French laboratories, including ours, initiated a project aimed at mapping the transcribed regions of the genome. The strategy employed was to systematically and randomly sequence cDNA clones isolated from libraries made from different tissues and organs of plants grown under various physiological conditions. The consortium released about 7,000 expressed sequenced tags (ESTs) in the dbEST database corresponding to approximately 3,500 unique genes. In the next phase of the programme, a YAC library with average inserts of 500 kbp has been prepared. We have now started to use the EST information to map the cDNA clones on these YACs. The most recent aspect of Arabidopsis sequencing is the ESSA (European Scientists Sequencing Arabidopsis) project, in which the aim is to describe 2.5 Mbp by the end of 1996. Genomic sequencing has revealed a very high gene density. Comparison of present genomic sequencing results with the EST data suggests that up to half of the genes might already be tagged with an EST. In collaboration with Carlos Quiros' group in Davis we have also analysed the conservation of a 30 kbp locus (Em 1, a late embryogenesis abundant protein gene) on chromosome 3 between Arabidopsis and several Brassica species. Progress on these various aspects will be reviewed. We shall also present some sequence comparisons between Arabidopsis and rice ESTs. These results suggest that it should be possible in the very near future to map a pool of common genes onto many different plant genomes. This should provide a common framework to integrate maps from different species and facilitate mapbased cloning of genes of agronomical importance.
拟南芥是一种十字花科杂草，其基因组较小，约为120兆碱基对，已被选作植物分子遗传学的模式物种。四年前，包括我们实验室在内的九个法国实验室组成的一个联盟启动了一个项目，旨在绘制该基因组的转录区域图谱。所采用的策略是对从在各种生理条件下生长的植物的不同组织和器官构建的文库中分离出的cDNA克隆进行系统随机测序。该联盟在dbEST数据库中发布了约7000个表达序列标签（EST），对应于大约3500个独特基因。在该项目的下一阶段，已制备了平均插入片段为500千碱基对的酵母人工染色体（YAC）文库。我们现在已开始利用EST信息将cDNA克隆定位到这些YAC上。拟南芥测序的最新进展是欧洲科学家测序拟南芥（ESS A）项目，其目标是在1996年底前测定250万碱基对。基因组测序显示基因密度非常高。将目前的基因组测序结果与EST数据进行比较表明，高达一半的基因可能已被EST标记。我们还与戴维斯的卡洛斯·基罗斯小组合作，分析了拟南芥与几种芸苔属物种之间第3号染色体上一个30千碱基对位点（Em1，一个晚期胚胎发生丰富蛋白基因）的保守性。将对这些不同方面的进展进行综述。我们还将展示拟南芥与水稻EST之间的一些序列比较。这些结果表明，在不久的将来应该能够将一组共同基因定位到许多不同的植物基因组上。这应该会提供一个共同框架，以整合来自不同物种的图谱，并促进对具有农学重要性的基因进行基于图谱的克隆。
