Arabidopsis thaliana Raw sequence reads
In Arabidopsis, little is known about the physiological significance of URT1 throughout plant development. These RAW seq data indicates that URT1 specifically targets a subset of XRN4 substrates in seedlings. In addition, small RNA deep sequencing (sRNA-seq) assays have identified HEAT SHOCK PROTEIN 90/70 (HSP90/70) and SMAX1-LIKE 4/5 (SMXL4/5) as the major targets of URT1 and SKI2 during the embryonic and seedling development, respectively. URT1 functions synergistically with the SKI complex to prevent generating of massive ectopic small interfering RNAs (siRNAs) from the HSP90/70 and SMXL4/5 loci via an RNA-DEPENDENT RNA POLYMERASE 6 (RDR6)-dependent pathway. Notably, by utilizing a weak point allele of urt1(-6), we have demonstrated that the uridylation activity of URT1 is largely non-essential for its regulatory role in embryonic and seedling development.