Fig. 1.

(A–D) Overview about the genomic structure of the wild type mouse mfrn-1 locus (A), construction of floxed allele with selectable neo-cassette (B), removal of neo-cassette to obtain a pure floxed allele (C) and graphical representation of a cre-mediated deletion of exon 2 (D), modified according to Troadec et al. [28]. (E) Analysis of neuronal knockout mice: Knockout occurs in the brains of 2 week-old neonates. Silver-stained polyacrylamide gel of a PCR showing the general presence of the conditional Mfrn-1 allele (Flox, intermediate band) and the absence of the wildtype allele (upper band, visible in non-transgenic animals only) in all mice of the breeding program, i.e. homozygosity for Flox. Those mice, which were positive for NES-driven Cre (neuronal KO) exhibited the corresponding KO allele (lowest bands) in brain tissue, which was absent in liver samples (L). Cre-negative mice contained only Flox, but no KO allele in the brain. ‘Glial KO’ refers to mice containing a GFAP-driven Cre, resulting in a glial Mfrn-1 KO. These mice were not subjected to closer examination as adults and are thus not subject of the present paper. However, they also show the expected KO band in the brain of neonates. M = molecular weight marker, low molecular weights on the upper edge.