Project description:Few families of signaling factors have been implicated in the control of development. Here we identify the neuropeptides nociceptin and somatostatin, a neurotransmitter and neuroendocrine hormone, as a class of developmental signals in chick and zebrafish. We show that signals from the anterior mesendoderm are required for the formation of anterior placode progenitors with one of the signals being somatostatin. Somatostatin controls ectodermal expression of nociceptin and both peptides regulate Pax6 in lens and olfactory progenitors. Consequently, loss of somatostatin and nociceptin signaling leads to severe reduction of lens formation. Our findings not only uncover these neuropeptides as developmental signals, but also identify a long-sought-after mechanism that initiates Pax6 in placode progenitors and may explain the ancient evolutionary origin of neuropeptides, pre-dating a complex nervous system. We used progenitors for anterior and posterior sensory placodes dissected from chick embryos HH5-7; these were either processed immediately or cultured for 5 hrs to hybridise to Affymetrix chick array. We aimed to identify genes that are co regualted with Pax6, a key regulator of lens and olfactory progenitor cells. Pax6 is normally present in anterior, but not posterior placode precursors, but upregulated in both after 5 hrs culture.
Project description:Few families of signaling factors have been implicated in the control of development. Here we identify the neuropeptides nociceptin and somatostatin, a neurotransmitter and neuroendocrine hormone, as a class of developmental signals in chick and zebrafish. We show that signals from the anterior mesendoderm are required for the formation of anterior placode progenitors with one of the signals being somatostatin. Somatostatin controls ectodermal expression of nociceptin and both peptides regulate Pax6 in lens and olfactory progenitors. Consequently, loss of somatostatin and nociceptin signaling leads to severe reduction of lens formation. Our findings not only uncover these neuropeptides as developmental signals, but also identify a long-sought-after mechanism that initiates Pax6 in placode progenitors and may explain the ancient evolutionary origin of neuropeptides, pre-dating a complex nervous system.
Project description:The transcription factor Pax6 is comprised of the paired domain (PD) and homeodomain (HD). In the developing forebrain, Pax6 is expressed in ventricular zone precursor cells and in specific subpopulations of neurons; absence of Pax6 results in disrupted cell proliferation and cell fate specification. Pax6 also regulates the entire lens developmental program. To reconstruct Pax6-dependent gene regulatory networks (GRNs), ChIP-seq studies were performed using lens and forebrain chromatin from mice. A total of 3,723 (forebrain) and 3,514 (lens) Pax6-containing peaks were identified, with ~70% of them found in both tissues and thereafter called “common” peaks. Analysis of Pax6-bound peaks identified motifs that closely resemble Pax6-PD, -PD/HD and -HD established binding sequences. Mapping of H3K4me1, H3K4me3, H3K27ac, H3K27me3 and RNA polymerase II revealed distinct types of tissue-specific enhancers bound by Pax6. Pax6 directly regulates cortical neurogenesis through activation (e.g. Dmrta1 and Ngn2) and repression (e.g. Ascl1, Fezf2, and Gsx2) of transcription factors. In lens, Pax6 directly regulates cell cycle exit control via components of FGF (Fgfr2, Ccnd1, and Prox1) and Wnt (Dkk3, Wnt7a, Lrp6, Bcl9l, and Ccnd1) signaling pathways. Collectively, these studies provide genome-wide analysis of Pax6-dependent GRNs in lens and forebrain and establish novel roles of Pax6 in organogenesis. Examination of Pax6 in mouse embryonic forebrain and newborn lens. We performed ChIP-seq on mouse E12.5 embryonic forebrain and newborn lens. Genome-wide binding sites of Pax6, H3K4me1, H3K4me3, H3K27ac, H3K27me3, and Pol2 were generated. We also performed RNA-seq on mouse E12.5 embryonic forebrain and newborn lens epithelial cells and fibers.
Project description:The transcription factor Pax6 is comprised of the paired domain (PD) and homeodomain (HD). In the developing forebrain, Pax6 is expressed in ventricular zone precursor cells and in specific subpopulations of neurons; absence of Pax6 results in disrupted cell proliferation and cell fate specification. Pax6 also regulates the entire lens developmental program. To reconstruct Pax6-dependent gene regulatory networks (GRNs), ChIP-seq studies were performed using lens and forebrain chromatin from mice. A total of 3,723 (forebrain) and 3,514 (lens) Pax6-containing peaks were identified, with ~70% of them found in both tissues and thereafter called “common” peaks. Analysis of Pax6-bound peaks identified motifs that closely resemble Pax6-PD, -PD/HD and -HD established binding sequences. Mapping of H3K4me1, H3K4me3, H3K27ac, H3K27me3 and RNA polymerase II revealed distinct types of tissue-specific enhancers bound by Pax6. Pax6 directly regulates cortical neurogenesis through activation (e.g. Dmrta1 and Ngn2) and repression (e.g. Ascl1, Fezf2, and Gsx2) of transcription factors. In lens, Pax6 directly regulates cell cycle exit control via components of FGF (Fgfr2, Ccnd1, and Prox1) and Wnt (Dkk3, Wnt7a, Lrp6, Bcl9l, and Ccnd1) signaling pathways. Collectively, these studies provide genome-wide analysis of Pax6-dependent GRNs in lens and forebrain and establish novel roles of Pax6 in organogenesis.