Early cleavage of preimplantation embryos is regulated by tRNAGln-TTG-derived small RNAs present in mature spermatozoa

Abstract

tRNA-derived small RNAs (tsRNAs) from spermatozoa could act as acquired epigenetic factors and contribute to offspring phenotypes. However, the roles of specific tsRNAs in early embryo development remain to be elucidated. Here, using pigs as a research model, we probed the tsRNA dynamics during spermatogenesis and sperm maturation and demonstrated the delivery of tsRNAs from semen-derived exosomes to spermatozoa. By microinjection of antisense sequences into in vitro fertilized oocytes and subsequent single-cell RNA-seq of embryos, we identified a specific functional tsRNA group (termed here Gln-TTGs) that participate in the early cleavage of porcine preimplantation embryos, probably by regulating cell cycle-associated genes and retrotransposons. We conclude that specific tsRNAs present in mature spermatozoa play significant roles in preimplantation embryo development.

Keywords: RNA; development; embryo; embryo cleavage; embryo development; epigenetics; exosome; fertility; preimplantation; sperm; sperm maturation; spermatogenesis; tRNA-derived small RNAs (tsRNAs); tRNAGln-TTG.