Project description:Nuclear-localized RNA binding proteins are involved in various aspects of RNA metabolism, which in turn modulates gene expression. However, the functions of nuclear-localized RNA binding proteins in plants are poorly understood. Here we report the functions of two proteins containing RNA recognition motifs, At RZ-1B and At RZ-1C, in Arabidopsis. At RZ-1B and At RZ-1C were localized to nuclear speckles and interacted with a spectrum of serine/arginine-rich (SR) proteins through their C-termini. At RZ-1C preferentially bound to purine-rich RNA sequences in vitro through its N-terminal RNA recognition motif. Disrupting the RNA-binding activity of At RZ-1C with SR proteins through over-expression of the C-terminus of At RZ-1C conferred defective phenotypes similar to those observed in At rz-1b/At rz-1c double mutants, including delayed seed germination, reduced stature, and serrated leaves. Loss of function of At RZ-1B and At RZ-1C was accompanied by defective splicing of many genes and global perturbation of gene expression. In addition, we found that At RZ-1C directly targeted FLC, promoting efficient splicing of FLC introns and likely also repressing FLC transcription. Our findings highlight the critical role of At RZ-1B/1C in regulating RNA splicing, gene expression, and many key aspects of plant development via interaction with proteins including SR proteins.
Project description:Nuclear-localized RNA binding proteins are involved in various aspects of RNA metabolism, which in turn modulates gene expression. However, the functions of nuclear-localized RNA binding proteins in plants are poorly understood. Here we report the functions of two proteins containing RNA recognition motifs, At RZ-1B and At RZ-1C, in Arabidopsis. At RZ-1B and At RZ-1C were localized to nuclear speckles and interacted with a spectrum of serine/arginine-rich (SR) proteins through their C-termini. At RZ-1C preferentially bound to purine-rich RNA sequences in vitro through its N-terminal RNA recognition motif. Disrupting the RNA-binding activity of At RZ-1C with SR proteins through over-expression of the C-terminus of At RZ-1C conferred defective phenotypes similar to those observed in At rz-1b/At rz-1c double mutants, including delayed seed germination, reduced stature, and serrated leaves. Loss of function of At RZ-1B and At RZ-1C was accompanied by defective splicing of many genes and global perturbation of gene expression. In addition, we found that At RZ-1C directly targeted FLC, promoting efficient splicing of FLC introns and likely also repressing FLC transcription. Our findings highlight the critical role of At RZ-1B/1C in regulating RNA splicing, gene expression, and many key aspects of plant development via interaction with proteins including SR proteins. mRNA-seq to look at the transcriptome and splicing differences between wild type and At rz-1b At rz-1c mutant of Arabidopsis thaliana