High resolution spatial transcriptomic and proteomic profiling of early primate gastrulation <i>in utero</i>

Early gastrulation represents a key stage in which several embryonic and extra-embryonic lineages are formed in the primitive streak to support embryonic development. However, very little is known about lineage specification events in the early primate gastrula. To gain molecular insights into mechanisms that organize this stage of primate development, we performed high-resolution spatial transcript and protein expression profiling of five sagittal sections from a cynomolgus macaque embryo at Carnegie Stage 6b, an early gastrulation stage. We established a molecular map of six major cell populations: the epiblast, primitive streak, amnion, endoderm, mesoderm, and primordial germ cells. We also uncovered a variety of lineage subtypes, as well as important signaling and transcriptional networks. In particular, we show that canonical WNT signaling is a driver of amnion fate progression. Together, this study provides a unique multiomic resource of an early primate gastrula with complete spatial information for future investigations.