Marillonnet S, Wessler S R
Department of Botany, University of Georgia, Athens 30602, USA.
Plant Cell. 1997 Jun;9(6):967-78. doi: 10.1105/tpc.9.6.967.
We previously reported that three alleles of the maize waxy (wx) gene were alternatively spliced as a result of the insertion of retrotransposons into intronic sequences. In addition, inefficient splicing of element sequences with the surrounding intron produced wild-type transcripts that presumably were responsible for the observed residual gene expression in the endosperm. In this study, we report that one of these alleles, wxG, has a tissue-specific phenotype with 30-fold more WX enzymatic activity in pollen than in the endosperm. Quantification of wxG-encoded transcripts in pollen and the endosperm demonstrates that this difference can be accounted for by tissue-specific differences in RNA processing. Specifically, there is approximately 30-fold more correctly spliced RNA in pollen than in the endosperm. Based on an analogy to similar examples of tissue-specific alternative splicing in animal systems, we hypothesize that the tissue-specific phenotype of the wxG allele may reflect differences in the concentration of splicing factors in these tissues.
我们之前报道过，由于反转录转座子插入内含子序列，玉米蜡质（wx）基因的三个等位基因发生了可变剪接。此外，元件序列与周围内含子的低效剪接产生了野生型转录本，推测这些转录本是胚乳中观察到的残余基因表达的原因。在本研究中，我们报道其中一个等位基因wxG具有组织特异性表型，其在花粉中的WX酶活性比在胚乳中高30倍。对花粉和胚乳中wxG编码转录本的定量分析表明，这种差异可以由RNA加工过程中的组织特异性差异来解释。具体而言，花粉中正确剪接的RNA比胚乳中多约30倍。基于与动物系统中组织特异性可变剪接的类似例子的类比，我们推测wxG等位基因的组织特异性表型可能反映了这些组织中剪接因子浓度的差异。
