The defect in astroglia at either prenatal or postnatal stage may be caused by synergistic interactions between astroglia and other cells, rather than cell-autonomous effects, as demonstrated by infection of AdCreM2 at E14.5 and induction of the hGFAP-CreERT2, R26R, β-cateninfl/fl mice at P0. This evidence concerns the gene PPIB and infection.