Cer1 Knockout mouse models

Cer1, mouse ortholog of human CER1, encodes Cerberus 1, a secreted cysteine-knot DAN family antagonist expressed in anterior visceral endoderm and anterior primitive streak that binds and sequesters Nodal, BMP4, and in some contexts Wnt ligands, sculpting the anterior signaling shield that permits head formation and restricts posteriorizing signals. Its Nodal-binding activity also contributes to left-right asymmetry and to the periodicity of Nodal expression during somite and node development, and human variants have been reported in laterality and cardiac malformation cohorts. Mouse nulls are viable and grossly normal, an instructive negative result attributable to overlapping antagonism from Lefty1, Lefty2, Dand5, Nog, and Chrd, so compound genetics rather than a single knockout is required to expose anterior patterning failure. Given viability, allele choice should favor either compound antagonist deletion for developmental endpoints or reporter and conditional alleles for lineage tracing of anterior endoderm. Humanization is warranted only when assaying human CER1 protein directly in differentiation or organoid readouts.

Whole body loss of Cer1 gives the clearest readout when the question is whether the gene is required at all. Follow up tissue work can still move to a conditional allele if lethality or compensation appears.