Schematic representations of the different cellular-specific conditional dystroglycan-null mice. Drawings illustrating the mouse cerebellum during embryonic (A) and postnatal development (B), the cellular organization at specified developmental period (A 1, A 2, B 1, B 2), and the localization of each promoter-driven Cre recombinase expression (A 2, B 2). Timeline of Cre activities is presented in (C). The nestin and GFAP promoters drive Cre expression in neuronal and glial precursors as early as E10.5  and E13.5 , respectively. However, the GFAP promoter does not express Cre in Purkinje cells . The PCP2-Cre promoter drives Cre expression in Purkinje cells beginning at P6 , whereas the the malpha6 promoter drives Cre expression in granule cells beginning at P4 .