Regulation of pri-miRNA processing by the hnRNP-like protein AtGRP7 in Arabidopsis.
Bottom Line: AtGRP7 overexpression caused a significant reduction in the level of 30 miRNAs and an increase for 14 miRNAs with a minimum log2 fold change of ± 0.5.Mutation of an arginine in the RNA recognition motif abrogated in vivo binding and the effect on miRNA and pri-miRNA levels, indicating that AtGRP7 inhibits processing of these pri-miRNAs by direct binding.Thus, AtGRP7 is an hnRNP-like protein with a role in processing of pri-miRNAs in addition to its role in pre-mRNA splicing.
Affiliation: Molecular Cell Physiology, Bielefeld University.Show MeSH
Mentions: Genome-wide transcriptome analysis of AtGRP7-ox plants had previously revealed an elevated steady-state abundance of the COPPER ZINC SUPEROXIDE DISMUTASE 2 (CSD2) transcript encoding a superoxide dismutase that uses copper as a metal cofactor (47). CSD2 is a target of the miR398 family, which comprises identical miRNAs encoded by MIR398b and MIR398c on chromosome V, and a miRNA with a 3’ U instead of G encoded by MIR398a on chromosome II (48,49). To test whether the altered CSD2 transcript level in AtGRP7-ox plants reflected an impact of AtGRP7 on miR398, we monitored miR398 levels using low molecular weight northern blot analysis. MiR398 steady-state abundance was reduced in AtGRP7-ox lines in the Col-2, L er and C24 accessions compared to the corresponding wt plants (Figure 1).