Biochemistry & Molecular Biology
Keck School of Medicine
USC / Norris Comprehensive Cancer Center
Cancer Cell Biology,
Cardiovascular & Skeletal Muscle Diseases,
The two broad interests of the Maxson laboratory are the molecular genetic basis of embryonic pattern formation and the identification and of genetic loci that influence cancer risk. In embryonic development, we focus on processes that regulate the development of the cranial neural crest, a popultion of multipotent cells that originate in the neural tube and migrate to distant sites, where they differentiate into a variety of cell types, including bone muscle, nerve, and cartilage. We are particuarly interested in genetic factors that control the multipotency of cranial neural crest. We are also interested in the formation and function of tissue boundaries between neural crest and other cell populations in embryonic development. We have shown that one such boundary, an interface between cranial neural crest and mesoderm in the developing skull, is crucial for proper growth and patterning of the calvarial bones. We have also identified genes in mice and humans that control this boundary. These include the transcription factor Twist1, which controls the boundary through the signaling molecules, EphA4, and Jagged1. Mutations in each of these genes cause human disorders that affect the development of the skull. Current topics under study include genetic and epigenetic factors controlling neural crest stem cell development and the role of ephrin and notch signaling in osteogenic precursor cell migration and specification. Our interest in cancer centers on the role of the Brca1 gene in ovarian cancer, and more recently, the characterization of the 8q24 locus in humans. This locus contains several conserved elements that function as enhancers and are capable of directing expression in specific tissues in which cancers develop, including breast and prostate. Current topics under study include the identification of genes regulated by the 8q24 enhancers.