The core transcriptome of mammalian placentas and the divergence of expression with placental shape

摘要

Abstract Introduction The placenta is arguably the most anatomically variable organ in mammals even though its primary function is conserved. Method Using RNA-Seq, we measured the expression profiles of 55 term placentas of 14 species of mammals representing all major eutherian superordinal clades and marsupials, and compared the evolution of expression across clades. Results We identified a set of 115 core genes which is expressed (FPKM ≥ 10 ) in all eutherian placentas, including genes with immune-modulating properties ( ANXA2 , ANXA1 , S100A11 , S100A10 , and LGALS1 ), cell-cell interactions ( LAMC1 , LUM , and LGALS1 ), invasion ( GRB2 and RALB ) and syncytialization ( ANXA5 and ANXA1 ). We also identified multiple pre-eclampsia associated genes which are differentially expressed in Homo sapiens when compared to the other 13 species. Multiple genes are significantly associated with placenta morphology, including EREG and WNT5A which are both associated with placental shape. Discussion 115 genes are important for the core functions of the placenta in all eutherian species analyzed. The molecular functions and pathways enriched in the core placenta align with the evolutionarily conserved functionality of the placenta. Highlights ? A core set of 115 non-housekeeping genes is expressed in 14 mammalian placentas. ? This placenta core transcriptome includes genes which regulate immunity, nutrient transport, and membrane repair. ? The genes required to form the placenta in the last common ancestor of eutherian mammals are represented in the placenta core transcriptome. ? Some genes which are implicated in pre-eclampsia ( KISS1 , PAPPA , ADAM12 ) are differentially expressed on the human lineage. ? Multiple genes are differentially expressed in association with placenta morphology, including EREG and WNT5A .