Recruitment of TRIM33 to cell-context specific PML nuclear bodies regulates Nodal signaling in mESCs. Recruitment of TRIM33 to cell-context specific PML nuclear bodies regulates Nodal signaling in mESCs

TRIM33 is a chromatin reader required for mesendoderm differentiation upon activation of Nodal signaling. But, its role in mESCs is still elusive. Here, we found that TRIM33 co-localizes with promyelocytic leukemia nuclear bodies (PML NBs) specifically in mESCs to mediate Nodal signaling-directed transcription of Lefty1/2. We showed that TRIM33 puncta formation in mESCs depends on PML and specific assembly of PML NBs. Moreover, TRIM33 and PML co-regulate Lefty1/2 expression in mESCs. In addition, both PML and mESCs-specific PML NBs are required for TRIM33 recruitment at Lefty1/2 loci. Remarkably, PML NBs directly associate with the Lefty1/2 loci in mESCs. Finally, a TurboID proximity labeling experiment confirmed that TRIM33 is highly enriched in the mESCs-specific PML NBs. Thus, our study provides the mechanistic insight about TRIM33 condensate in regulating Nodal signaling-directed transcription in mESCs, it also reveals that PML NBs recruit distinct sets of client proteins in cell context dependent manner. Overall design: ChIP was performed as previously described (Wang et al., 2017; Xi et al., 2011). CUT&TAG was performed with Hieff NGS Fast Tagment DNA Library Prep Kit for Illumina kit as manufacture protocol described. Illumina sequencing was performed after ChIP or CUT&TAG experiment.