YY1-dependent transcriptional regulation manifests at the morula stage

YY1 plays multifaceted roles in various cell types. We recently reported that YY1 regulates nucleosome organization in early mouse embryos (Sakamoto et al. Genes Dev 2023). However, despite the impaired nucleosome organization in the absence of YY1, the transcriptome was minimally affected in eight-cell embryos. We then hypothesized that YY1 might prepare a chromatin environment to regulate gene expression at later stages. To test this possibility, we performed a transcriptome analysis at the morula stage. We found that a substantial number of genes are aberrantly expressed in the absence of YY1. Furthermore, our analysis revealed that YY1 is required for the transcription of retrotransposons in early embryos. Total RNA-seq was performed using mouse early embryos.