Associate Professor, Neurobiology
Ph.D. , University of Massachusetts (1977)
Address: W1442 BSTWR
200 Lothrop Street
Pittsburgh, PA 15213-2536
Motoneuron development and spinal cord patterning
Dr. Lance-Jones' research focuses on the development of motoneurons and their axonal projections in the vertebrate embryo. During early embryogenesis, motoneurons acquire unique molecular profiles as a result of their position with respect to specific signaling centers. Subsequently, these molecular profiles are translated into stereotyped patterns of motor columns or nuclei and specific patterns of connectivity with both somatic and visceral targets. Trainees in Dr. Lance-Jones' laboratory are currently studying aspects of these processes in three different groups of developing motoneurons. The muscles of the hindlimb are innervated by motoneurons located within the lateral motor columns of the lumbosacral cord. Members of Dr. Lance-Jones' lab are addressing the roles of Hox transcription factors in the early diversification of lumbosacral motoneuron progenitors using both in ovo electroporation in the chick embryo as well as assessments of motoneuron organization in Hox loss-of-function mice embryos. Little is known about the origins of a second group of motoneurons in lumbosacral regions, the postganglionic motoneurons that innervate caudal or pelvic viscera and arise from the caudal neural crest. Avian chimera production and cell tracing experiments are being employed to identify the specific origins of pelvic ganglia and to characterize spatial and temporal features of molecular differentiation. Finally, studies carried out by Dr. Lance-Jones' research group are addressing questions about the identity and distribution of axon guidance cues influencing target choice among motoneuron populations that innervate extraocular muscles.
How and when do motoneurons acquire a target identity? How is the early limb bud populated by muscle cell precursors? How does the early spinal cord acquire differences along its cranio-caudal axis? Trainees in Dr. Lance-Jones' laboratory have the opportunity to study embryonic patterning at tissue, cell and molecular levels. In vivo embryonic surgery is frequently combined with new techniques for identifying different types of embryonic cells. Such techniques might include long-lasting fluorescent cell markers, monoclonal antibodies, retroviral vectors, and/or gene probes. Currently, laboratory members are specifically looking at the roles of hox genes and paraxial mesoderm in the early regional development of the spinal cord.
Hox transcription factors influence motoneuron identity through the integrated actions of both homeodomain and non-homeodomain regions.
Intrinsic properties guide proximal abducens and oculomotor nerve outgrowth in avian embryos.
Implementation of a longitudinal mentored scholarly project: an approach at two medical schools.
Restricted patterns of Hoxd10 and Hoxd11 set segmental differences in motoneuron subtype complement in the lumbosacral spinal cord.
Ectopic expression of Hoxd10 in thoracic spinal segments induces
motoneurons with a lumbosacral molecular profile and axon projections to the limb.
Programming neural Hoxd10: in vivo evidence that early node-associated
signals predominate over paraxial mesoderm signals at posterior spinal levels.
© Copyright 2001 - University
of Pittsburgh Department of Neurobiology