DIFFERENTIAL ORGAN-SPECIFIC EXPRESSION OF 3 POLY(A)-BINDING-PROTEIN GENES FROM ARABIDOPSIS-THALIANA
DIFFERENTIAL ORGAN-SPECIFIC EXPRESSION OF 3 POLY(A)-BINDING-PROTEIN GENES FROM ARABIDOPSIS-THALIANA
复制标题
DOI：
10.1073/pnas.90.14.6686
复制
发表时间：
1993-07-15
影响因子：
11.1
通讯作者：
MEAGHER, RB
中科院分区：
文献类型：
--
作者：
BELOSTOTSKY, DA;MEAGHER, RB
多聚腺苷酸结合蛋白（PABP）被认为是真核细胞的重要组成部分;在酵母中PABP编码基因的缺失导致致死表型。PABP参与转录后调控的许多方面，包括mRNA周转和翻译起始。从酵母，非洲爪蟾，和人类PABP序列之间的保守区域设计的一套巢式简并PCR引物被用来扩增拟南芥基因组DNA片段。用基因组PCR探针对基因组和cDNA文库进行杂交筛选，分离出编码PABPs的三个不同的拟南芥基因PAB 1、PAB 3和PAB 5。所有三个序列都含有预期的四个RNA识别基序。这些基因之间的序列多样性等于或超过动物和真菌序列之间的多样性。其中一个基因PAB 5及其cDNA已完全测序。其开放阅读框编码一个73.2 kDa的蛋白质，该蛋白质含有来自不同物种的PABP的特征性氨基酸基序。此外，体外合成的PAB 5蛋白与poly（A）-Sepharose具有高度特异性结合。所有三个基因分离显示器官特异性表达模式。PAB 5和PAB 3 RNA仅在花器官中检测到，在未成熟花中表达水平最高。PAB 1 RNA主要在根中观察到，在未成熟花中不太丰富，并且在任何其他检查的器官（茎、叶、成熟花、长角果）中未检测到。这表明PABP在植物器官特异性转录后调控中可能具有独特的作用。
Poly(A)-binding Protein (PABP) is considered an essential component of a eukaryotic cell; deletion of the PABP-coding gene in yeast leads to a lethal phenotype. PABP is implicated in numerous aspects of posttranscriptional regulation, including mRNA turnover and translational initiation. A nested set of degenerate PCR primers designed from regions conserved among yeast, Xenopus, and human PABP sequences was used to amplify genomic DNA fragments from Arabidopsis thaliana. Hybridization screening of genomic and cDNA libraries with a genomic PCR probe led to the isolation of three diverse Arabidopsis genes encoding PABPs, PAB1, PAB3, and PAB5. All three sequences contain the expected four RNA-recognition motifs. Sequence diversity between these genes equals or exceeds the diversity among animal and fungal sequences. One of the genes, PAB5, and its cDNA were completely sequenced. Its open reading frame encodes a 73.2-kDa protein containing a number of amino acid motifs characteristic of PABPs from different species. Moreover, in vitro synthesized PAB5 protein bound to poly(A)-Sepharose with high specificity. All three genes isolated showed organ-specific patterns of expression. PAB5 and PAB3 RNAs were detected only in floral organs, with the highest level of expression in immature flowers. PAB1 RNA was observed predominantly in roots, was less abundant in immature flowers, and was not detected in any other organ examined (stems, leaves, mature flowers, siliques). This suggests a potentially unique role for PABPs in organ-specific posttranscriptional regulation in plants.