The development of a multicellular organism from a single celled fertilized egg has long fascinated Biologists. Over the past thirty years, the major molecular components that control development have been identified. The interaction between these components has been well characterized, and nowhere better illustrated than the hierarchy of factors that establish the segmented body plan of the fruit fly, Drosophila melanogaster. Many of these factors constitute the conserved genetic toolkit required for the development of all animal body plans. We study one set of proteins that are part of this genetic toolkit: the HOX proteins.
The HOX proteins we study are required for determining the number of segments that form, Fushi tarazu, and for determining the identity/structure that a segment will develop, Proboscipedia and Sex combs reduced. The HOX proteins are transcription factors that regulate the expression of genes. Although most transcription factors are thought to be composed of modular domains that mediate an unique aspect of transcription factor function like DNA binding, transcriptional activation/repression, and binding regulatory factors, the HOX proteins are proving to be quite dissimilar to this view of the archetypic transcription factor in being composed in most cases of small peptide motifs that make small and differential contributions to overall HOX activity. We are interested in how HOX proteins work as transcription factors and what processes they control in developmental programs.