Embryonic gene transcription in the spiny mouse (Acomys cahirinus): an investigation into the embryonic genome activation.

Our understanding of genetic mechanisms driving early embryonic development is primarily based on experiments conducted on mice, however translation of findings can be limited by physiological differences between mice and humans. To address this, we investigated whether the spiny mouse (Acomys cahirinus) is a closer model of early human embryonic development due to their more human-like endocrine profile. We therefore characterised the initiation of gene transcription in the spiny mouse embryo and compared the pattern of gene expression during the embryonic genome activation (EGA) with common mouse and human embryos. Naturally-mated spiny mouse embryos were obtained at the 2-cell, 4-cell and 8-cell stages of development (n=4 biological replicates per stage). RNA-Seq of these samples produced 709.1M paired-end reads in total. De novo assembly of reads was conducted using Trinity. Embryo-specific transcripts were extracted from the de novo assembly and added to the reference spiny mouse transcriptome. Transcription was first detected between the 2-cell and 4-cell stages for the majority of genes (n=3,428), with fewer genes first transcribed between the 4-cell and 8-cell stages (n=1,150). The pattern of gene expression in spiny mouse embryos during this period of development is more human-like than common mouse embryos. This is the first evidence the spiny mouse may provide a more suitable model of human embryonic development. The improved reference Acomys cahirinus transcriptome is publically accessible, further increasing the value of this tool for ongoing research. Further investigation into early development in the spiny mouse is warranted.