Regulation of the gene expression of ferredoxin-NADP^+ reductase by light and nitarte in rice.

从水稻叶片和根cDNA文库中分别克隆了铁氧还蛋白-NADP ^+还原酶（FNR）的全长cDNA克隆，并进行了序列测定。核苷酸序列显示，光合FNR在高等植物中高度保守，而水稻根FNR与叶酶的同源性要低得多（49%）。根FNR基因的表达受硝酸盐诱导，而不受氨诱导，表明后者是一个硝酸盐诱导基因。根FNR基因全长3897个核苷酸，由6个外显子和5个内含子组成。通过引物延伸分析确定转录起始位点，其位于ATG翻译起始密码子上游64位。5 ′-侧翼区含有典型的TATA-、CAAT-和潜在的Sl-结合盒。启动子区有4个ATCAA（A/C）及其2个倒位TTTGAT序列，3 '端非翻译区有3个TGTAA基序。将水稻根和菠菜叶FNR基因的5 '侧翼区进行比较，发现两者之间没有显著的相似性。

Full-length cDNA clones for ferredoxin-NADP^+ reductase (FNR) have been isolated from rice leaf and root cDNA libraries, respectively and they were sequenced. The nucleotide sequences showed that photosynthetic FNRs are highly conserved among higher plants, whereas rice root FNR showed much less homology to the leaf enzyme (49%) . The gene expression of the root FNR was induced by nitrate, but not by ammonia, suggesting that the latter gene is a nitrate-inducible gene.A genomic clone of the gene corresponding to the root FNR has been isolated and its nucleotide sequence was determined. The root FNR clone contains 3897 nucleotides of the gene which consists of six exons inter-rupted by five introns. The transcription start site was determined by primer extension analysis which locates 64 upstream of the ATG translation start codon. The 5'-flanking region conatins cannonical TATA-, CAAT-and a potential Spl-binding boxes. Four ATCAA (A/C) and its two inverted TTTGAT sequences are localized in the promoter region and a TGTAA motif occurs three-times in the 3'-untranslated region. No significant similarity was found when the 5'-flanking region was comapred between the rice root and spinach leaf FNR genes.