Alex Hajnal

Signal transduction in Caenorhabditis elegans

The roundworm (Nematode) Caenorhabditis elegans has become a popular model organism that is used to address a variety of questions in Biology. We are interested in the signals that cells exchange in order to control cell proliferation and differentiation during the development of the animal. In particular, the development of the hermaphrodite vulva serves us as a paradigm to study intercellular communication and cell fate determination. During vulval development, the coordinate action of three evolutionary conserved signal transduction pathways (the Wingless, Ras and Notch pathways) controls the differentiation of vulval cells that form this organ during larval development.

In a first project, we are studying how the receptors for growth factor signals are localized and how their activities are regulated in the vulval precursor cells. We are currently focusing on the epidermal growth factor receptor, since inappropriate activation of this receptor is involved of the formation of different types of tumors in humans. In a second project, we are studying the process of cell invasion during vulval development. We are investigating the signals, by which the vulval precursor cells induce the adjacent anchor cell to invade into the vulval epithelium. The activation of cell invasion is thought to be an initiating event during the formation of tumor metastases. In a third project, we are studying how intercellular signaling controls the morphogenesis of the vulval cells undergoing terminal differentiation to determine the shape and size of the organ.

The insights gained from our studies on vulval development uncover the fundamental rules governing organogenesis and can be applied to understand the formation of complex organs in higher animals.