A transgenic Cre mouse line for the study of cortical and hippocampal development

Wnt signaling regulates cortical and hippocampal development. In a previous study we found that a particular Wnt receptor, Frizzled9 (Fzd9), was selectively expressed in both the developing and adult hippocampus. Taking advantage of the specificity of this promoter, we generated a transgenic cre mouse line using the putative control elements of the Fzd9 gene. In the Fzd9-cre mice, Cre is mainly detected in the developing cortex and hippocampus and is confined to the CA fields and dentate gyrus in adults. Furthermore, by crossing the Fzd9-cre mouse with the ROSA26 reporter line, we examined the activity of Cre and found that it has very high recombination efficiency. Thus, this mouse line will likely prove to be a useful tool for studying cortical and hippocampal development via activation or inactivation of interesting genes.