PT  - JOURNAL ARTICLE
AU  - Laura A. Moody
AU  - Ester Rabbinowitsch
AU  - Hugh G. Dickinson
AU  - Roxaana Clayton
AU  - David M. Emms
AU  - Jane A. Langdale
TI  - A Musashi-Related Protein is Essential for Gametogenesis in Arabidopsis
AID  - 10.1101/579714
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 579714
4099  - http://biorxiv.org/content/early/2019/03/16/579714.short
4100  - http://biorxiv.org/content/early/2019/03/16/579714.full
AB  - Musashi (Msi) proteins are an evolutionarily conserved group of RNA-binding proteins, required for targeted control of mRNA translation during many important developmental processes in animals. Most notably, Msi proteins play important roles during both spermatogenesis and oogenesis. Msi proteins also exist in plants but these are largely uncharacterized. Here we report the functional characterization of an Arabidopsis Msi ortholog ABORTED GAMETOPHYTE 2 (AOG2), which encodes a protein containing two RNA recognition motifs and an ER-targeting signal. AOG2-GFP translational fusions were localized to the ER in transient assays, suggesting that AOG2 most likely binds to ER-targeted mRNAs. We show that disrupted AOG2 function leads to a high rate of both ovule and seed abortion, and that homozygous loss of function mutants are embryo lethal. Furthermore, we demonstrate that AOG2 is required to establish asymmetry during pollen mitosis I, and that loss of AOG2 function leads to loss of pollen viability. Collectively the results reveal that AOG2 is required for the establishment of polarity and/or the progression of mitosis during gametophyte development in Arabidopsis, and thus Msi-related proteins have an evolutionarily conserved role in gametogenesis in both animals and plants.SIGNIFICANCE STATEMENT ABORTED GAMETOPHYTE 2 (AOG2) encodes a Musashi-related RNA-binding protein that is required for gametogenesis and embryogenesis in Arabidopsis. AOG2 is required for the establishment of polarity and/or the progression of mitosis during gametophyte development in Arabidopsis, and thus Musashi-related proteins have an evolutionarily conserved role in gametogenesis in both animals and plants.