Bmp4 Knockout mouse models

Bmp4, ortholog of human BMP4, encodes the principal dorsoventral patterning ligand of the mammalian embryo, a processed homodimer acting through BMPR1A with BMPR2 to drive SMAD1, SMAD5, and SMAD8 phosphorylation and Id gene induction during gastrulation, primordial germ cell allocation, limb and craniofacial mesenchyme patterning, and later hair follicle and hematopoietic niche signaling. Extracellular tuning by noggin, chordin, gremlin, and twisted gastrulation sets the effective gradient, and human heterozygous deletions cause microphthalmia with coloboma, orofacial clefting, and digit anomalies, matching a strict dosage requirement. Constitutive nulls fail at gastrulation with absent mesoderm, so conditional floxed alleles are obligatory, and hypomorphic or haploinsufficient models are better matched to human dosage disease than complete deletion. Because Bmp2 and Bmp7 overlap in most of these fields and heterodimers are physiologically relevant, compound conditionals are frequently necessary. Choose Cre drivers such as Wnt1-Cre, Prrx1-Cre, or Krt14-Cre according to whether the endpoint is craniofacial, appendicular, or epidermal.

Whole body loss of Bmp4 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.