Obesity is mainly due to excessive food intake. IRX3 and IRX5 have been suggested as determinants of obesity in connection with the intronic variants of FTO, but how these genes contribute to obesity via changes in food intake remains unclear. Here, we show that mice doubly heterozygous for Irx3 and Irx5 mutations exhibit lower food intake with enhanced hypothalamic leptin response. By lineage tracing and single-cell RNA sequencing using the Ins2-Cre system, we identify a previously unreported radial glia-like neural stem cell population with high Irx3 and Irx5 expression in early postnatal hypothalamus and demonstrate that reduced dosage of Irx3 and Irx5 promotes neurogenesis in postnatal hypothalamus leading to elevated numbers of leptin-sensing arcuate neurons. Furthermore, we find that mice with deletion of Irx3 in these cells also exhibit a similar food intake and hypothalamic phenotype. Our results illustrate that Irx3 and Irx5 play a regulatory role in hypothalamic postnatal neurogenesis and leptin response.
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http://dx.doi.org/10.1038/s42255-021-00382-y | DOI Listing |
PLoS One
December 2024
Dept. of Human and Animal Cell Lines, Leibniz-Institute DSMZ, Braunschweig, Germany.
Homeobox genes encode transcription factors which organize differentiation processes in all tissue types including the hematopoietic compartment. Recently, we have reported physiological expression of TALE-class homeobox gene IRX1 in early myelopoiesis restricted to the megakaryocyte-erythroid-progenitor stage and in early B-cell development to the pro-B-cell stage. In contrast, sister homeobox genes IRX2, IRX3 and IRX5 are aberrantly activated in the corresponding malignancies acute myeloid leukemia (AML) and B-cell progenitor acute lymphoid leukemia.
View Article and Find Full Text PDFJ Comp Neurol
December 2024
School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
A gene cadre orchestrates the normal development of sensory and non-sensory cells in the inner ear, segregating the cochlea with a distinct tonotopic sound frequency map, similar brain projection, and five vestibular end-organs. However, the role of genes driving the ear development is largely unknown. Here, we show double deletion of the Iroquois homeobox 3 and 5 transcription factors (Irx3/5 DKO) leads to the fusion of the saccule and the cochlear base.
View Article and Find Full Text PDFbioRxiv
October 2024
School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
The mammalian inner ear houses the vestibular and cochlear sensory organs dedicated to sensing balance and sound, respectively. These distinct sensory organs arise from a common prosensory region, but the mechanisms underlying their divergence remain elusive. Here, we showed that two evolutionarily conserved homeobox genes, and , are required for the patterning and segregation of the saccular and cochlear sensory domains, as well as for the formation of auditory sensory cells.
View Article and Find Full Text PDFBone
January 2025
Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Program in Developmental & Stem Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada. Electronic address:
Iroquois homeobox gene 3 (Irx3) and Irx5 encode transcription factors that play crucial roles in limb development and bone formation. Previous studies using knockout mice have revealed a role of Irx3 and Irx5 in osteogenesis in young adult mice. However, whether these genes are also essential for bone homeostasis in adulthood and contribute to bone diseases remain poorly understood.
View Article and Find Full Text PDFbioRxiv
June 2024
Department of Neurobiology, University of Utah; Salt Lake City, 84105, USA.
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