2022 Vol. 13, No. 7
RNA binding protein LIN28A is mainly localized in the nucleolus in early embryo development, and it can reside in a complex containing NCL and TRIM28 to repress Dux and promote rRNA expression. Meanwhile, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to ribosomal stress and activation of p53 which in turn binds to and activates 2C transcription factor Dux. LIN28 is a crucial factor to bridge two adjacent processes after ZGA: on one hand, LIN28 shuts down the 2-cell/4-cell program, and on the other hand, LIN28 promotes a pro-proliferation and anabolic program and a shift away from the 2C-like state with a metabolically inactive and translationally inert program.