Stottmann et al.  suggest that the spinal defect in Noggin null embryos results from a failure to maintain a closed neural tube due to a defective paraxial mesoderm . Yip et al.  also had shown that the mesodermal extracellular matrix plays an important role in maintaining neuroepithelial rigidity of the spinal neural tube during neurulation . Embryos were cultured in the presence of chlorate, which functions to inhibit sulfation of heparan sulphate proteoglycans (HSPGs) in the extracellular matrix of the mesoderm. This treatment not only resulted in an expedited bending of the DLHPs but also elicited an unnatural shape of neural tube due to a convex shaped mesoderm. However, removal of the paraxial mesoderm does not prevent closure of the spinal neural tube .