中文摘要：

抗神经炎素(维生素 B (1 )) 是为有机体的必要混合物。它包含嘧啶戒指结构和噻唑戒指结构。抗神经炎素的这二一半独立地被综合然后一起联合了。这里，我们报导 AtTHIC 的分子的描述，它在 Arabidopsis 涉及抗神经炎素生合成。AtTHIC 类似于 Escherichia 关口 i ThiC，它在初核质涉及嘧啶生合成。AtTHIC 的 Heterologous 表示能机能上地补充 E 的 thiC 大美人异种。关口 i。由在它的倡导者区域的 T-DNA 插入的 AtTHIC 表示的 Downregulation 在植物导致了抗神经炎素内容的激烈的减小，击倒的变异的 thic1 在正常文化条件下面显示出白化体(白叶子) 和致命的显型。thic1 异种能被抗神经炎素的补充救，它的缺点功能能被 AtTHIC cDNA 的表示补充。短暂表示分析表明 AtTHIC 蛋白质指向质体和叶绿体。AtTHIC 强烈在叶子，花和 siliques 被表示， AtTHIC 的抄写是外来的抗神经炎素调整的 down。在结论， AtTHIC 是在 Arabidopsis 的抗神经炎素生合成小径涉及嘧啶合成的基因，并且我们的结果为阐明提供一些新线索在植物的抗神经炎素生合成的小径。

英文摘要：

Thiamine （vitamin B1） is an essential compound for organisms. It contains a pyrimidine ring structure and a thiazole ring structure. These two moieties of thiamine are synthesized independently and then coupled together. Here we report the molecular characterization of AtTHIC, which is involved in thiamine biosynthesis in Arabidopsis. AtTHIC is similar to Escherichia coli ThiC, which is involved in pyrimidine biosynthesis in prokaryotes. Heterologous expression of AtTHIC could functionally complement the thiC knock-out mutant of E. coll. Downregulation of AtTHIC expression by T-DNA insertion at its promoter region resulted in a drastic reduction of thiamine content in plants and the knock-down mutant thicl showed albino （white leaves） and lethal phenotypes under the normal culture conditions. The thicl mutant could be rescued by supplementation of thiamine and its defect functions could be complemented by expression ofAtTHIC cDNA. Transient expression analysis revealed that the AtTHIC protein targets plastids and chloroplasts. AtTHIC was strongly expressed in leaves, flowers and siliques and the transcription of AtTHIC was downregulated by extrinsic thiamine. In conclusion, AtTHIC is a gene involved in pyrimidine synthesis in the thiamine biosynthesis pathway of Arabidopsis, and our results provide some new clues for elucidating the pathway of thiamine biosynthesis in plants.