Establishing the roles of Calcineurin/NFAT calcium signaling in early craniofacial morphogenesis
Licia Selleri, Professor
UC San Francisco
Closed. This professor is continuing with Fall 2023 apprentices on this project; no new apprentices needed for Spring 2024.
Craniofacial malformations are among the most common birth defects. Cellular and molecular programs underlying neural and craniofacial development are mediated by various signaling pathways, including those directed by calcium. Conserved involvement of calcium signaling has been implicated in craniofacial morphogenesis across species, from avian to mammal, but the mechanisms by which calcium directs the outgrowth of individual craniofacial structures are unknown. Differential expression of calmodulin (CaM), a calcium sensor, has been shown to direct midface outgrowth, specifically beak lengths, in Darwin’s finches. In humans, changes in intracellular calcium caused by a gain of function mutation in CACNA1C, which encodes the L-type calcium channel (LTCC) Cav1.2, lead to Timothy Syndrome, characterized by autism, cardiac dysfunction, and craniofacial defects. Intracellular calcium elevations activate downstream signaling, such as the calcineurin (CaN)/NFAT cascade. CaN, a calmodulin-dependent phosphatase, directs nuclear localization and transcriptional activity of NFAT. Interestingly, two genes encoding members of the CaN/NFAT pathway, DYRK1A and RCAN1 (or DSCR1), are located within the Down syndrome critical region. DYRK1A is a kinase that directs the rapid export of NFAT from the nucleus, and RCAN1 is an endogenous CaN inhibitor. Synergy between these proteins reduces nuclear NFAT abundance, with ensuing mental retardation and craniofacial abnormalities in Down syndrome patients. Mouse models lacking both Nfatc2 and Nfatc4 also exhibit reduced head length, further underscoring the involvement of the CaN/NFAT pathway in craniofacial morphogenesis. Our aim is to understand how calcium signaling regulates coordination of growth of different craniofacial structures during development. In pursuit of this, our immediate goal is to focus on understanding molecular and cellular mechanisms by which CaN/NFAT signaling directs facial outgrowth in species with different midface lengths, including lizards, chicks, and mice.
Role: The undergraduate will be come familiar with dissections of embryos from different species (mouse, chick, lizards) and will learn how to visualize mRNA expression of genes encoding CaN/NFAT signaling components by in situ hybridization on embryonic heads. S/he will also learn how to quantitate gene expression by qRT-PCR on embryonic head structures. S/he will also learn how to visualize localization of proteins produced by CaN/NFAT signaling components on embryos of different species by immunofluorescence.
Qualifications: Curious, interested in developmental biology and mechanisms underlying evolution, hard-worker, with solid foundations in cell biology, and/or molecular biology, and/or biochemistry, and/or developmental biology.
Day-to-day supervisor for this project: Tiange Qu (UC Berkeley Graduate), Graduate Student
Hours: to be negotiated
Off-Campus Research Site: 513 Parnassus Avenue, HSW 710 UCSF San Francisco
Related website: https://selleri.ucsf.edu
Biological & Health Sciences