Requirement of Npc1 and availability of cholesterol for early embryonic cell movements in zebrafish.

Niemann-Pick disease, type C (NP-C), often associated with Niemann-Pick disease, type C1 (NPC1) mutations, is a cholesterol-storage disorder characterized by cellular lipid accumulation, neurodegeneration, and reduced steroid production. To study NPC1 function in vivo, we cloned zebrafish npc1 and analyzed its gene expression and activity by reducing Npc1 protein with morpholino (MO)-oligonucleotides. Filipin staining in npc1-morphant cells was punctate, suggesting abnormal accumulation of cholesterol.

Visualization of Gli activity in craniofacial tissues of hedgehog-pathway reporter transgenic zebrafish.

Background: The Hedgehog (Hh)-signaling pathway plays a crucial role in the development and maintenance of multiple vertebrate and invertebrate organ systems. Gli transcription factors are regulated by Hh-signaling and act as downstream effectors of the pathway to activate Hh-target genes. Understanding the requirements for Hh-signaling in organisms can be gained by assessing Gli activity in a spatial and temporal fashion.

Zebrafish con/disp1 reveals multiple spatiotemporal requirements for Hedgehog-signaling in craniofacial development.

Background: The vertebrate head skeleton is derived largely from cranial neural crest cells (CNCC). Genetic studies in zebrafish and mice have established that the Hedgehog (Hh)-signaling pathway plays a critical role in craniofacial development, partly due to the pathway's role in CNCC development. Disruption of the Hh-signaling pathway in humans can lead to the spectral disorder of Holoprosencephaly (HPE), which is often characterized by a variety of craniofacial defects including midline facial clefting and cyclopia 12.

Deciphering the role of Shh signaling in axial defects produced by ethanol exposure.

Background: The phenotype of embryos exposed to ethanol is complex and likely due to multiple alterations in developmental pathways. We have previously demonstrated that Sonic hedgehog signaling (Shh-s) was reduced in both chicken and zebrafish embryos when exposed to ethanol.

Methods: There are many tissues affected by embryonic ethanol exposure, and in this article we explore the development of axial tissues, using zebrafish embryos.

Molecular changes associated with teratogen-induced cyclopia.

Background: Exposure of zebrafish embryos to a number of teratogens results in cyclopia, but little is known about the underlying molecular changes.

Methods: Using zebrafish embryos, we compare the effects cyclopamine, forskolin, and ethanol delivered starting just before gastrulation, on gene expression in early axial tissues and forebrain development.

Results: Although all three teratogens suppress gli1 expression, they do so with variable kinetics, suggesting that while suppression of Shh signaling is a common outcome of these three teratogens, it is not a common cause of the cyclopia.

Expression profiles of ndel1a and ndel1b, two orthologs of the NudE-Like gene, in the zebrafish.

NudE-Like (NDEL1/NUDEL), through its interaction with LIS1 and DISC1, has been implicated in the etiology of neurological disorders such as lissencephaly and schizophrenia, respectively. Subsequently, a large portion of the research done on the function of NDEL1 has been specifically targeted to its role in brain development while ignoring its function in other developing and adult tissues. To begin a more global exploration of NDEL1's function, this study characterizes the developmental expression pattern of the NDEL1 orthologs in the zebrafish embryo.

Sonic hedgehog rescues cranial neural crest from cell death induced by ethanol exposure.

Alcohol is a teratogen that induces a variety of abnormalities including brain and facial defects [Jones, K. & Smith, D. (1973) Lancet 2, 999-1001], with the exact nature of the deficit depending on the time and magnitude of the dose of ethanol to which developing fetuses are exposed.