Multiple defects in mouse stem cell based embryo models lacking all Hox function [ChIP-Seq]

While gene inactivation approaches and full cluster deletions have revealed their critical functions during early development, the effect of removing all Hox function has remained elusive due to both biological and technological challenges. We have used mouse gastruloids, an ES cells-derived embryo model where Hox genes are properly activated in time and space, to assess the effect of their complete absence.

We report that gastruloids lacking Hox function can still elongate and reach a general shape resembling their control counterparts, with a well-established AP polarity. However, unlike controls, they fail to produce any endoderm and are unable to properly segment their presomitic mesoderm into persistent somite-like structures. Instead, they produce a type of mesoderm with a more anterior identity.