Gene expression in autumn leaves
Gene expression in autumn leaves
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DOI：
10.1104/pp.012732
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发表时间：
2003-02-01
期刊：
影响因子：
7.4
通讯作者：
Jansson, S
中科院分区：
文献类型：
--
作者：
Bhalerao, R;Keskitalo, J;Jansson, S
制备了两个 cDNA 文库，一个来自田间生长的白杨 (Populus tremula) 树的叶子，在秋季叶子出现任何明显衰老迹象之前收获，另一个来自温室生长的白杨 (Populus tremula X tremulaides) 年轻但完全展开的叶子。从两个文库获得表达的序列标签（EST；分别为 5,128 和 4,841）。根据修改后的慕尼黑蛋白质序列研究所分类方案，利用来自三个不同数据库的信息，开发了 EST 的半自动注释和功能分类方法。两个文库中的基因表达模式显着不同。在秋叶文库中，编码金属硫蛋白、早期光诱导蛋白和半胱氨酸蛋白酶的 EST 最丰富。编码参与呼吸和脂质和色素分解的其他蛋白酶和蛋白质的克隆，以及与压力相关的基因，也得到了很好的体现。我们鉴定了许多已知的衰老相关基因的同源物，以及编码半胱氨酸蛋白酶的 7 个不同基因、2 个编码天冬氨酸蛋白酶、5 个编码金属硫蛋白以及 35 个在秋叶中上调的其他基因。我们还间接估计秋叶中质体蛋白的合成率低于嫩叶的 10%。
Two cDNA libraries were prepared, one from leaves of a field-grown aspen (Populus tremula) tree, harvested just before any visible sign of leaf senescence in the autumn, and one from young but fully expanded leaves of greenhouse-grown aspen (Populus tremula X tremuloides). Expressed sequence tags (ESTs; 5,128 and 4,841, respectively) were obtained from the two libraries. A semiautomatic method of annotation and functional classification of the ESTs, according to a modified Munich Institute of Protein Sequences classification scheme, was developed, utilizing information from three different databases. The patterns of gene expression in the two libraries were strikingly different. In the autumn leaf library, ESTs encoding metallothionein, early light-inducible proteins, and cysteine proteases were most abundant. Clones encoding other proteases and proteins involved in respiration and breakdown of lipids and pigments, as well as stress-related genes, were also well represented. We identified homologs to many known senescence-associated genes, as well as seven different genes encoding cysteine proteases, two encoding aspartic proteases, five encoding metallothioneins, and 35 additional genes that were up-regulated in autumn leaves. We also indirectly estimated the rate of plastid protein synthesis in the autumn leaves to be less that 10% of that in young leaves.