ALY RNA-Binding Proteins Are Required for Nucleocytosolic mRNA Transport and Modulate Plant Growth and Development

作者：Christina Pfaff, Hans Friedrich Ehrnsberger, María Flores‐Tornero, Brian B. Sørensen, Thomas E. O. Schubert, Gernot Längst, Joachim Griesenbeck, Stefanie Sprunck, Marion Grasser, Klaus D. Grasser · 发表于：PLANT PHYSIOLOGY · 年份：2018 · DOI：10.1104/pp.18.00173 · 被引用次数：64 · 研究领域：RNA Research and Splicing、RNA modifications and cancer、Plant Molecular Biology Research

The regulated transport of mRNAs from the cell nucleus to the cytosol is a critical step linking transcript synthesis and processing with translation. However, in plants, only a few of the factors that act in the mRNA export pathway have been functionally characterized. Flowering plant genomes encode several members of the ALY protein family, which function as mRNA export factors in other organisms. Arabidopsis (Arabidopsis thaliana) ALY1 to ALY4 are commonly detected in root and leaf cells, but they are differentially expressed in reproductive tissue. Moreover, the subnuclear distribution of ALY1/2 differs from that of ALY3/4. ALY1 binds with higher affinity to single-stranded RNA than double-stranded RNA and single-stranded DNA and interacts preferentially with 5-methylcytosine-modified single-stranded RNA. Compared with the full-length protein, the individual RNA recognition motif of ALY1 binds RNA only weakly. ALY proteins interact with the RNA helicase UAP56, indicating a link to the mRNA export machinery. Consistently, ALY1 complements the lethal phenotype of yeast cells lacking the ALY1 ortholog Yra1. Whereas individual aly mutants have a wild-type appearance, disruption of ALY1 to ALY4 in 4xaly plants causes vegetative and reproductive defects, including strongly reduced growth, altered flower morphology, as well as abnormal ovules and female gametophytes, causing reduced seed production. Moreover, polyadenylated mRNAs accumulate in the nuclei of 4xaly cells. Our resu...