Daniel H. Turnbull

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Recent studies suggest that neurons born in the developing basal forebrain migrate long distances perpendicularly to radial glia and that many of these cells reach the developing neocortex. This form of tangential migration, however, has not been demonstrated in vivo, and the sites of origin, pathways of migration and final destinations of these neurons in(More)
Proximal-distal outgrowth of the vertebrate limb bud is regulated by the apical ectodermal ridge (AER), which forms at an invariant position along the dorsal-ventral (D/V) axis of the embryo. We have studied the genetic and cellular events that regulate AER formation in the mouse. In contrast to implications from previous studies in chick, we identified two(More)
There are currently no noninvasive imaging methods available for auditory brain mapping in mice, despite the increasing use of genetically engineered mice to study auditory brain development and hearing loss. We developed a manganese-enhanced MRI (MEMRI) method to map regions of accumulated sound-evoked activity in awake, normally behaving mice. To(More)
To elucidate the role of cardiac myosin-binding protein-C (MyBP-C) in myocardial structure and function, we have produced mice expressing altered forms of this sarcomere protein. The engineered mutations encode truncated forms of MyBP-C in which the cardiac myosin heavy chain-binding and titin-binding domain has been replaced with novel amino acid residues.(More)
We used ultrasound image-guided injections of high-titer retroviral vectors to obtain widespread introduction of genes into the mouse nervous system in utero as early as embryonic day 8.5 (E8.5). The vectors used included internal promoters that substantially improved proviral gene expression in the ventricular zone of the brain. To demonstrate the utility(More)
Given the importance of genetically modified mice in studies of mammalian brain development and human congenital brain diseases, MRI has the potential to provide an efficient in vivo approach for analyzing mutant phenotypes in the early postnatal mouse brain. The combination of reduced tissue contrast at the high magnetic fields required for mice, and the(More)
The contribution of early cell lineage to regional fate in the mammalian forebrain remains poorly understood. Previous lineage-tracing studies using retroviral methods were only begun at mid-neurogenesis and have suffered from region-specific retroviral silencing. We have been able to study cell lineage in the telencephalon from the onset of neurogenesis by(More)
A basic limitation of the study of development in the mouse is the inaccessibility of the embryos, which are encased in the maternal uterus. We demonstrate the first use of ultrasound backscatter microscopy for guiding injections of cells and other agents into early stage mouse embryos. Cells were injected into the mouse neural tube cavity as early as 9.5(More)
Little is known about the genetic pathways and cellular processes responsible for regional differences in cerebellum foliation, which interestingly are accompanied by regionally distinct afferent circuitry. We have identified the Engrailed (En) homeobox genes as being crucial to producing the distinct medial vermis and lateral hemisphere foliation patterns(More)
BACKGROUND The increasing number of transgenic and targeted mutant mice with embryonic cardiac defects has resulted in the need for noninvasive techniques to examine cardiac structure and function in early mouse embryos. We report the first use of a novel 40-MHz ultrasound imaging system in the study of mouse cardiac development in utero. METHODS AND(More)