CONICET | Buscador de Institutos y Recursos Humanos

The hypothalamus is a brain region that regulates several basic homeostatic processes including reproducion, metabolism, energy balance, circadian rhythms, the response to stress and several behaviours. Its high anatomical complexity and location in the ventral forebrain has made the hypothalamus a difficult region to study. The recent availability of gene expression atlases has helped to create a framework to study how the different neuronal types carry out theirdifferentiation programs. One of the transcription factors expressed during hypothalamic development is Islet-1 (Isl1). This member of the LIM-homeodomain family has been shown to regulate cell fate specification in multiple tissues and species, in particular the spinal cord, pancreas and heart. In the hypothalamus, it has been shown that Isl1 has a role in regulating gene expression of some neuronal populations of the arcuate nucleus, but its role in other hypothalamic nuclei has not been described yet. With the aim of exploring this topic, we have used immunofluorescence to create a map of Isl1 expression pattern in several timepoints in the developing mouse hypothalamus. Our results show that Isl1 is expressed in an extense area in the early developing hypothalamus and that it later concentrates in compact areas and nuclei, such asthe arcuate nucleus (ARC), subparaventricular area (SPa), anterior hypothalamus (AH), periventricular nucleus (PeVN), the dorsomedial nucleus, the thalamic zona incerta (ZI) and the retrothalamic nucleus (RTN). With the purpose of elucidating the function that Isl1 exerts in the hypothalamus, we are doing functional studies in mice using a conditional knockout model which allows the depletion of Isl1 at specific timepoints during embryonic development. Our research will shed light on the genetics of neuronal differentiation within the mammalian hypothalamus.