What is the role of maternally provided Cdx2 mRNA in early mouse embryogenesis?

Genetic knockout studies in the mouse model first revealed the essential role of zygotically derived Cdx2 transcription factor during the later stages of blastocyst formation, characterized by a lack of functioning trophectoderm. However, the extent to which the potential provision of maternally derived Cdx2 affects preimplantation development has proved much less simple to address. Within the last year, two reports have been published arguing for and against a distinct functional role for maternal Cdx2. This commentary aims to discuss the approaches, results and interpretations of both studies in an attempt to resolve the apparent conflict and to constructively advance collective understanding.