A novel senescence-associated gene encoding γ-aminobutyric acid (GABA):pyruvate transaminase is upregulated during rice leaf senescence
A novel senescence-associated gene encoding γ-aminobutyric acid (GABA):pyruvate transaminase is upregulated during rice leaf senescence
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DOI：
10.1111/j.1399-3054.2004.00430.x
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发表时间：
2005-01-01
影响因子：
6.4
通讯作者：
Chen, SCG
中科院分区：
文献类型：
--
作者：
Ansari, MI;Lee, RH;Chen, SCG
Os 12基因在水稻叶片衰老过程中特异性上调。CV.台农67），并对其进行了功能鉴定。该基因的蛋白质编码区由19个外显子组成，编码516个氨基酸，具有推定的线粒体靶向序列和吡哆醛5 '-磷酸结合结构域的保守序列。在大肠杆菌中过表达的重组Os 12融合蛋白显示出谷氨酸依赖性γ-氨基丁酸（GABA）转氨酶（EC 2.6.1.19）活性。Os 12基因在水稻中的表达模式的检查表明，Os 12特异性转录诱导衰老叶片。Osl 2蛋白积累的时间曲线与水稻叶片中的谷氨酸依赖的GABA转氨酶活性的时间曲线相关，在S3衰老期表达水平最高。讨论了GABA转氨酶在水稻叶片衰老过程中的潜在作用。
The gene Osl2, which is specifically upregulated during leaf senescence in rice (Oryza sativa L. cv. Tainong 67), was cloned and functionally characterized. The protein coding region of the gene consists of 19 exons encoding 516 amino acids, with a putative mitochondrial targeting sequence and conserved sequence of the pyridoxal 5'-phosphate-binding domain. The recombinant Osl2 fusion protein over-expressed in Escherichia coli displays pyruvate-dependent gamma-aminobutyric acid (GABA) transaminase (EC 2.6.1.19) activity. Examination of the expression patterns of the Osl2 gene in rice reveals that Osl2-specific transcripts are induced in the senescing leaves. The temporal profile of Osl2 protein accumulation is correlated with that of pyruvate-dependent GABA transaminase activity in rice leaves, with the highest expression level at the S3 senescent stage. The potential role for GABA transaminase during rice leaf senescence is discussed.