Characterization of structural and regulatory genes of rice nitrite reductase.

以硝酸盐诱导的水稻绿苗为材料，构建了叶片和根的cDNA文库。从每个文库中克隆两种不同类型的亚硝酸盐还原酶（NiR）cDNA并测序。其中一组的DNA序列与分离的NiR蛋白序列有一个开放的阅读框，而另一组的cDNA克隆在前者的阅读框中增加了一个93 bp的序列。该插入序列具有真核mRNA中5'和3'剪接点的共有序列。以水稻核基因组DNA为模板，通过PCR技术证实了该插入DNA序列存在于水稻核基因组DNA中。水稻NiR基因的完整测序可能为阐明NiR cDNA中插入序列的这种不寻常存在的生理意义提供线索。

Leaf and root cDNA libraries were constructed in lambdagt 11 phage vector from nitrate-induced greening rice seedlings. Two different types of nitrite reductase (NiR) cDNA from each library were cloned and sequenced. DNA sequence of one group had an open reading frame matched with the isolated NiR protein sequence, while cDNA clone from the other had an addtional sequence of 93 bp in the reading frame of the former clone. The insertion sequence has consensus sequence of 5' and 3' splice junction in eukaryotic mRNA. This inserted DNA sequence was confirmed to exist in rice nuclear genomic DNA by PCR technique using the genomic DNA as a template. Complete sequencing of the rice NiR gene may provide a clue to elucidating physiological significance of this unusual presence of an intervening sequence in NiR cDNA.