Krüppel-like factor 7 is required for olfactory bulb dopaminergic neuron development

Krüppel-like factor 7 (KLF7) belongs to the large family of KLF transcription factors, which comprises at least 17 members. Within this family, KLF7 is unique since its expression is strictly restricted within the nervous system during development. We have previously shown that KLF7 is required for neuronal morphogenesis and axon guidance in selected regions of the nervous system, including hippocampus, olfactory bulbs and cortex, as well as in neuronal cell cultures. In the present work, we have furthered our analysis of the role of KLF7 in central nervous system development. By gene expression analysis during brain embryogenesis, we found significant alterations in dopaminergic neurons in Klf7 null mice. In particular, the tyrosine hydroxylase (TH) and dopamine transporter (Dat) transcripts are strongly decreased in the olfactory bulbs and ventral midbrain at birth, compared to wild-type littermates. Interestingly, Klf7-mutant mice show a dramatic reduction of TH-positive neurons in the olfactory bulbs, but no change in GABAergic or midbrain dopaminergic neurons. These observations raise the possibility that a lack of a KLF family member affects dopaminergic neuron development.