Expression of the LIM-homeodomain gene Lmx1a in the postnatal mouse central nervous system.

The LIM-homeodomain transcription factor Lmx1a plays critical roles in roof plate formation as well as in the cell fate determination of midbrain dopaminergic neurons during embryonic development, but its function in the adult brain remains unknown. In the present study, as the first step in exploring its function in adult brain, we examined the expression of Lmx1a in the mouse central nervous system (CNS) from birth to adulthood by in situ hybridization. Lmx1a was expressed at high levels in the posterior hypothalamic area, supremammillary nucleus, ventral premammillary nucleus, subthalamic nucleus, ventral tegmental area, compact part of the substantia nigra and parabrachial nucleus from birth to adulthood, and co-localized with its paralogue Lmx1b in these regions. On the other hand, Lmx1a expression in the cochlear nuclei, medial cerebellar nucleus and superior vestibular nucleus was only observed until postnatal day (P) 30 and showed no colocalization with Lmx1b. Lmx1a-expressing neurons in the ventral midbrain were dopaminergic as evidenced by co-expression with tyrosine hydroxylase in these regions. Furthermore, Lmx1a expression was also found in the choroid plexuses and ependymal cells, although its expression was only detected during the first two postnatal weeks. These results suggest that Lmx1a may be involved in postnatal development as well as in maintenance of some aspects of normal brain function.

Expression of the transcription factor GATA3 in the postnatal mouse central nervous system.

GATA binding protein 3 (GATA3) is an important regulator of central nervous system (CNS) development, but its expression pattern in the postnatal CNS has not been studied. In the present study, we examined the distribution of GATA3 mRNA in the mouse CNS at different postnatal stages by in situ hybridization. During the first 2 weeks of postnatal development, numerous GATA3-expressing cells were found in the intergeniculate leaf, ventral lateral geniculate nucleus, pretectal nucleus, nucleus of the posterior commissure, superior colliculus, inferior colliculus, periaqueductal grey, substantia nigra and raphe nuclei. Few notable changes in the profile of GATA3 expression occurred over this time period. As postnatal development progressed, however, GATA3 expression weakened, and was maintained in only a few regions of the adult CNS. Throughout the brain, we found that GATA3-expressing cells were NeuN-positive, and no colocalization with glial fibrillary acidic protein (GFAP) was observed. In the substantia nigra, GATA3 was exclusively expressed in cells of the reticulate part and some of which were found to be GABAergic. This study presents a comprehensive overview of GATA3 expression in the CNS throughout postnatal life, and the dynamics that we observed provide insights for further investigations of the roles of GATA3 in postnatal development and the maintenance of the mature CNS.