Dendritic localization of the transcriptional co-repressor Groucho/TLE1 in cortical and cerebellar neurons.

In the present study we show that the transcription factor Groucho/TLE1 (TLE1) is expressed in virtually all major cortical subdivisions, hippocampus, amygdala, and thalamus, as well as in the cerebellum of the adult rat brain. In both neocortex and subcortical structures, TLE1 expression was mostly localized to neurons. In addition to the expected nuclear localization, TLE1 immunoreactivity was also detected in apical dendritic shafts of neocortical layer III and V pyramidal cells and in Purkinje cell dendrites. These results demonstrate that TLE1 expression occurs in the mature nervous system and suggest that this protein may perform new functions outside of the nucleus in selected cortical and cerebellar neurons.