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NFIC
About: NFIC is a research topic. Over the lifetime, 68 publications have been published within this topic receiving 1682 citations.
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TL;DR: An estrogen-regulated combinatorial network including cell-specific cis- and trans-regulators of CCND1 expression where ERalpha collaborates with other transcription factors associated with the ER-positive breast cancer phenotype, including FoxA1 and NFIC is revealed.
Abstract: Estrogen stimulates the proliferation of the most common type of human breast cancer that expresses estrogen receptor α (ERα) through the activation of the cyclin D1 (CCND1) oncogene. However, our knowledge of ERα transcriptional mechanisms remains limited. Hence, it is still elusive why ERα ectopically expressed in ER-negative breast cancer cells (BCC) is functional on ectopic reporter constructs but lacks activity on many endogenous target genes, including CCND1. Here, we show that estradiol (E2) stimulation of CCND1 expression in BCC depends on a novel cell-type-specific enhancer downstream from the CCND1 coding region, which is the primary ERα recruitment site in estrogen-responsive cells. The pioneer factor FoxA1 is specifically required for the active chromatin state of this enhancer and as such is crucial for both CCND1 expression and subsequent cell cycle progression. Interestingly, even in BCC, CCND1 levels and proliferation are tightly controlled by E2 through the establishment of a negative feedforward loop involving the induction of NFIC, a putative tumor suppressor capable of directly repressing CCND1 transcription. Taken together, our results reveal an estrogen-regulated combinatorial network including cell-specific cis- and trans-regulators of CCND1 expression where ERα collaborates with other transcription factors associated with the ER-positive breast cancer phenotype, including FoxA1 and NFIC.
285 citations
TL;DR: The Nfic mutation is the first mutation described that affects primarily tooth root formation and should greatly aid the understanding of postnatal tooth development.
Abstract: The mammalian tooth forms by a series of reciprocal epithelial-mesenchymal interactions. Although several signaling pathways and transcription factors have been implicated in regulating molar crown development, relatively little is known about the regulation of root development. Four genes encoding nuclear factor I (NFI) transcription-replication proteins are present in the mouse genome: Nfia, Nfib, Nfic, and Nfix. In order to elucidate its physiological role(s), we disrupted the Nfic gene in mice. Heterozygous animals appear normal, whereas Nfic−/− mice have unique tooth pathologies: molars lacking roots, thin and brittle mandibular incisors, and weakened abnormal maxillary incisors. Feeding in Nfic−/− mice is impaired, resulting in severe runting and premature death of mice reared on standard laboratory chow. However, a soft-dough diet mitigates the feeding impairment and maintains viability. Although Nfic is expressed in many organ systems, including the developing tooth, the tooth root development defects were the prominent phenotype. Indeed, molar crown development is normal, and well-nourished Nfic−/− animals are fertile and can live as long as their wild-type littermates. The Nfic mutation is the first mutation described that affects primarily tooth root formation and should greatly aid our understanding of postnatal tooth development.
193 citations
TL;DR: This study has revealed an important signaling mechanism in which TGF‐β/BMP signaling relies on a Smad‐dependent mechanism in regulating Nfic expression via Shh signaling to control root development.
Abstract: Transforming growth factor beta (TGF-beta)/bone morphogenetic protein (BMP) signaling is crucial for regulating epithelial-mesenchymal interaction during organogenesis, and the canonical Smad pathway-mediated TGF-beta/BMP signaling plays important roles during development and disease. During tooth development, dental epithelial cells, known as Hertwig's epithelial root sheath (HERS), participate in root formation following crown development. However, the functional significance of HERS in regulating root development remains unknown. In this study we investigated the signaling mechanism of Smad4, the common Smad for TGF-beta/BMP signaling, in HERS in regulating root development. Tissue-specific inactivation of Smad4 in HERS results in abnormal enamel and dentin formation in K14-Cre;Smad4(fl/fl) mice. HERS enlarges but cannot elongate to guide root development without Smad4. At the molecular level, Smad4-mediated TGF-beta/BMP signaling is required for Shh expression in HERS and Nfic (nuclear factor Ic) expression in the cranial neural crest (CNC)-derived dental mesenchyme. Nfic is crucial for root development, and loss of Nfic results in a CNC-derived dentin defect similar to the one of K14-Cre;Smad4(fl/fl) mice. Significantly, we show that ectopic Shh induces Nfic expression in dental mesenchyme and partially rescues root development in K14-Cre;Smad4(fl/fl) mice. Taken together, our study has revealed an important signaling mechanism in which TGF-beta/BMP signaling relies on a Smad-dependent mechanism in regulating Nfic expression via Shh signaling to control root development. The interaction between HERS and the CNC-derived dental mesenchyme may guide the size, shape, and number of tooth roots.
125 citations
TL;DR: The knockout analysis of the fourth and last member of this gene family, Nfix, is reported and it is shown that the expression level of tetranectin, a plasminogen-binding protein involved in mineralization, is specifically downregulated in bones of NFIX-deficient mice.
Abstract: The transcription factor family of nuclear factor I (NFI) proteins is encoded by four closely related genes: Nfia, Nfib, Nfic, and Nfix. A potential role for NFI proteins in regulating developmental processes has been implicated by their specific expression pattern during embryonic development and by analysis of NFI-deficient mice. It was shown that loss of NFIA results in hydrocephalus and agenesis of the corpus callosum and that NFIB deficiency leads to neurological defects and to severe lung hypoplasia, whereas Nfic knockout mice exhibit specific tooth defects. Here we report the knockout analysis of the fourth and last member of this gene family, Nfix. Loss of NFIX is postnatally lethal and leads to hydrocephalus and to a partial agenesis of the corpus callosum. Furthermore, NFIX-deficient mice develop a deformation of the spine, which is due to a delay in ossification of vertebral bodies and a progressive degeneration of intervertebral disks. Impaired endochondral ossification and decreased mineralization were also observed in femoral sections of Nfix-/- mice. Consistent with the defects in bone ossification we could show that the expression level of tetranectin, a plasminogen-binding protein involved in mineralization, is specifically downregulated in bones of NFIX-deficient mice.
121 citations
TL;DR: It is shown that cells expressing osterix are mesenchymal progenitors contributing to all relevant cell types during morphogenesis, underscoring importance of the PTHrP–PPR system during root morphogenesis and tooth eruption.
Abstract: Dental root formation is a dynamic process in which mesenchymal cells migrate toward the site of the future root, differentiate and secrete dentin and cementum. However, the identities of dental mesenchymal progenitors are largely unknown. Here we show that cells expressing osterix are mesenchymal progenitors contributing to all relevant cell types during morphogenesis. The majority of cells expressing parathyroid hormone-related peptide (PTHrP) are in the dental follicle and on the root surface, and deletion of its receptor (PPR) in these progenitors leads to failure of eruption and significantly truncated roots lacking periodontal ligaments. The PPR-deficient progenitors exhibit accelerated cementoblast differentiation with upregulation of nuclear factor I/C (Nfic). Deletion of histone deacetylase-4 (HDAC4) partially recapitulates the PPR deletion root phenotype. These findings indicate that PPR signalling in dental mesenchymal progenitors is essential for tooth root formation, underscoring importance of the PTHrP-PPR system during root morphogenesis and tooth eruption.
97 citations