Fig. 1

The epitope-tagged minimal RNA-binding protein ‘FLAG-BD’ binds the SOC1 mRNA. A The Arabidopsis BRN1 protein contains three RRM domains (1–3) that bind the SOC1 mRNA 3’UTR [18]. Only two RRM domains (1–2) are necessary for Bruno-like proteins to bind their targets [29]. The BRN1 protein inhibits SOC1 translation [18], and this is thought to be mediated via the protein region between RRM 2 and 3. We generated a FLAG epitope-tagged (asterisk) truncated BRN1 protein with only RRM domains 1 and 2 (FLAG-BD, bottom). Figure created with BioRender. B Western blot of the FLAG-immunoprecipitation in plants with and without the FLAG-BD transgene. The three wt Col and FLAG-BD samples are biological replicates. PEP is an unrelated protein used as a loading control. FT = Flow Through fraction unbound to the FLAG antibody. Arrowheads mark the predicted size of the protein detected. C FLAG-IP followed by RNA extraction and qRT-PCR of samples from (B). AT2G20610 is an unrelated gene used as a negative control. Each biological replicate is shown as a circle. The bar represents the average and error bars represent the standard deviation between three or more biological replicates. P-value is calculated by using an unpaired t-test with Welch's correction. The RIP experiment was repeated twice (Rep 1 / Rep 2) using distinct biological replicate plants