Revisiting poly(A)-binding proteins: Multifaceted regulators during gametogenesis and early embryogenesis

Abstract

Post-transcriptional regulation faces a distinctive challenge in gametes. Transcription is limited when the germ cells enter the division phase due to condensed chromatin, while gene expression during gamete maturation, fertilization, and early cleavage depends on existing mRNA post-transcriptional coordination. The dynamics of the 3ʹ-poly(A) tail play crucial roles in defining mRNA fate. The 3ʹ-poly(A) tail is covered with poly(A)-binding proteins (PABPs) that help to mediate mRNA metabolism and recent work has shed light on the number and function of germ cell-specific expressed PABPs. There are two structurally different PABP groups distinguished by their cytoplasmic and nuclear localization. Both lack catalytic activity but are coupled with various roles through their interaction with multifunctional partners during mRNA metabolism. Here, we present a synopsis of PABP function during gametogenesis and early embryogenesis and describe both conventional and current models of the functions and regulation of PABPs, with an emphasis on the physiological significance of how germ cell-specific PABPs potentially affect human fertility.