Research Interest
Spinal Cord Development
.
I am interested in understanding the molecular mechanisms that control
the generation of different neuronal types along the anterior-posterior
(A-P) axis of the spinal cord, using motor neurons as a model system.
Spinal motor neurons in the ventral spinal cord extend axons to innervate
peripheral muscle targets originating at equivalent A-P levels during
embryonic development. I am studying the functions of the Hox-c cluster
genes in order to understand how different motor neurons are generated
along the A-P axis and how motor neuron identity affects
axonal path finding and target selection. Different Hox-c cluster genes
are expressed in distinct but overlapping domains along the A-P axis
of the spinal cord. Using chick neural explants in an in vitro culture
system, I have
demonstrated that both paraxial mesoderm and tissues around Hensen's
node initiate the patterned expression of different Hox-c genes in the
spinal cord. The secreted molecules from these tissues that induce this
patterning event include Fgf8, Gdf11, and retinoic acid. Currently,
I am trying to identify genes acting down-stream of these signaling
molecules that are required for patterned Hox-c gene expression. I am
also addressing the functions of Hox-c genes in defining motor neuron
identity and target selection by mis-expressing or removing Hox-c gene
function specifically in the spinal motor neurons using transgenic approaches.
Representative Publications
- Welsh, J., Liu, J.-P.,
and Efstratiadis, A. "Cloning of PCR-amplified Total cDNA: Construction
of a Mouse Oocyte cDNA Library" (1990) Gene Anal. Techn. 7, 5-17.
- Liu, J-P., Baker,
J., Perkins, A. S., Robertson, E. J., and Efstratiadis, A. "Mice
Carrying Null Mutations of the Genes Encoding Insulin-like Growth
Factor I (Igf-1) and Type 1 IGF Receptor (Igf1r)" (1993) Cell
75, 59-72.
- Baker, J., Liu, J-P.,
Robertson, E. J., and Efstratiadis, A. "Role of Insulin-like
Growth Factors in Embryonic and Postnatal Growth" (1993) Cell
75, 73-82.
- Sell, C., Rubini, M.,
Rubin, R., Liu, J-P., Efstratiadis, A., and Baserga, R. "Simian
Virus 40 Large Tumor Antigen is Unable to Transform Mouse Embryonic
fibroblasts Lacking Type 1 Insulin-like Growth Factor
Receptor" (1993) Proc. Natl. Acad. Sci. USA 90, 11217-11221.
- Zeitlin, S., Liu,
J-P., Chapman, DL., Papaioannou, VE., Efstratiadis, A. "Increased
Apoptosis and Early Embryonic Lethality in Mice Nullizygous for the
Huntington's Disease Gene Homologue" (1995) Nat. Genet. 11(2):
155-63.
- Liu, J-P. and
Jessell, T.M."A Role for RhoB in the Delamination of Premigratory
Neural Crest Cells from the dorsal Neural Tube" (1998) Development
125, 5055-5067.
- Liu, A-X., Du, W., Liu,
J-P., Jessell T.M., and Prendergast, G. "RhoB Alteration
is Necessary for the Apoptotic and Antineoplastic Responses to Farnesyltransferase
Inhibitors" (2000) Mole. Cell. Biol. 20(16): 6105-6113.
- Liu, A-X., Rane, N.,
Liu, J-P., and Prendergast, G. "RhoB is Dispensable for
Mouse Development, but It Modifies Susceptibility to Tumor Formation
as Well as Cell Adhesion and Growth Factor Signaling in Transformed
Dells" (2001) Mole. Cell. Biol. 21(20):
6906-6912.
- Liu, J-P.,
Laufer, E. and Jessell, T.M. "Assigning the Positional Identity
of Spinal Motor Neurons: Rostrocaudal Patterning of Hox-c Expression
by FGFs, Gdf11, and Retinoids"(2001) Neuron 32: 997-1012.
For more information e-mail
jl7nf@virginia.edu
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