Leaf-specifically expressed genes for polypeptides destined for chloroplasts with domains of σ70 factors of bacterial RNA polymerases in Arabidopsis thaliana
Leaf-specifically expressed genes for polypeptides destined for chloroplasts with domains of σ70 factors of bacterial RNA polymerases in Arabidopsis thaliana
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DOI：
10.1073/pnas.94.26.14948
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发表时间：
1997-12-23
影响因子：
11.1
通讯作者：
Kobayashi, H
中科院分区：
文献类型：
--
作者：
Isono, K;Shimizu, M;Kobayashi, H
细菌型RNA聚合酶的sigma样因子的基因还没有从任何多细胞真核生物的特点，虽然他们可能在质体光合作用基因的表达中发挥了至关重要的作用。我们已经克隆了三个不同的cDNA，命名为SIG 1，SIG 2和SIG 3，多肽具有的氨基酸序列的结构域保守的西格玛（70）因子从高等植物拟南芥的细菌RNA聚合酶。每个基因作为每个单倍体基因组的一个拷贝存在，而没有在基因组中杂交的任何另外的序列。利用绿色荧光蛋白进行的瞬时表达分析表明，SIG 2和SIG 3 ORF的N-末端区域可以作为转运肽输入叶绿体。所有三个SIG基因的转录本检测到在叶中，但不是在根中，并诱导在叶片中的暗适应植物在快速响应光照。与我们以前的分析结果的质体光合作用基因的转录的组织特异性调节，这些结果表明，基因的表达水平可能会影响转录通过调节RNA聚合酶的活性在一个绿色组织特异性的方式。
Genes for sigma-like factors of bacterial-type RNA polymerase have not been characterized from any multicellular eukaryotes, although they probably play a crucial role in the expression of plastid photosynthesis genes. We have cloned three distinct cDNAs, designated SIG1, SIG2, and SIG3, for polypeptides possessing amino acid sequences for domains conserved in sigma(70) factors of bacterial RNA polymerases from the higher plant Arabidopsis thaliana. Each gene is present as one copy per haploid genome without any additional sequences hybridized in the genome. Transient expression assays using green fluorescent protein demonstrated that N-terminal regions of the SIG2 and SIG3 ORFs could function as transit peptides for import into chloroplasts. Transcripts for all three SIG genes were detected in leaves but not in roots, and were induced in leaves of dark-adapted plants in rapid response to light illumination. Together with results of our previous analysis of tissue-specific regulation of transcription of plastid photosynthesis genes, these results indicate that expressed levels of the genes may influence transcription by regulating RNA polymerase activity in a green tissue-specific manner.