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. 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.