Research

In developmental biology, the goal is to determine the molecular events that regulate growth and development of a fertilized egg into a multicellular organism. One part of this development is the differentiation of mesoderm into muscle. During Drosophila embryogenesis, mesoderm formation starts at gastrulation in the ventral furrow cells. Eventually, a subset of the mesodermal cells will give rise to the somatic body wall muscles, which is organized into 30 separate and distinct muscles repeated within each segment of the embryo. I have isolated and studied a homeobox gene, muscle segment homeobox (msh) expressed during Drosophila embryogenesis. The msh gene is expressed in developing neuroblasts early in embryogenesis. Later in embryogenesis, msh is expressed dorsal lateral cells in each thoracic and abdominal segments, which will form body wall muscles. As embryogenesis continues, the msh-expressing cells are expanded as myoblasts fuse to form muscle fibers. Msh expression is reduced or absent in twist or snail mutants, which do not form the mesodermal germ layer, confirming that msh expression is in the mesoderm. Ectopic expression of msh in the mesodermal cells leads to defects in the developing musculature suggesting that muscle defects are at the level of recruitment and/or formation of muscle precursor cells. Since msh is a homeobox gene, the msh protein acts as a transcription factor and "turns on" other genes, which are important in muscle differentiation.

Selected Publications

Lord, P.C.W., Lin, M. H., Hales, K. H. and Storti, R.V. 1995. Normal Expression and the Effects of Ectopic Expression of the Drosophila muscle segment homeobox (msh) gene Suggests a Role in Differentiation and Patterning of Embryonic Muscles. Developmental Biology 171:627-640.

Gremke, L.G., Lord, P.C.W., Sabacan, L., Lin, S.C., Wohlwill, A., and Storti, R.V. 1993. Coordinate Regulation of Drosophila Tropomyosin Gene Expression is Controlled by Multiple Muscle-Type-Specific Positive and Negative Enhancer Elements. Developmental Biology 159:513-527.

Lord, P.C.W., Wilmoth, L.M.G., Mizel, S.B., and McCall, C.E. 1991. Expression of Interleukin 1 alpha and beta Genes by Human Polymorphonuclear Leukocytes. Journal of Clinical Investigations. 87:1312-1321.

Lord, P.C.W., Rothschild, C.B., DeRose, R.T., and Kilpatrick, B.A. 1989. Human Cytomegalovirus RNAs Immunoprecipitated by Multiple Systemic Lupus Erythematosus Antisera. Journal of General Virology 70:2383-2396.

Van Stee, E.W., Wynns, P.C., and Morrison, M.P. 1981. Distribution and Disposition of Morpholine in the Rabbit. Toxicology 20:53-60.