Prof. Dr. Hajnal Alex

Main Field(s) of Research, Abstract
Signal transduction in Caenorhabditis elegans
The roundworm (Nematode) Caenorhabditis elegans is a popular model organism that is used to address a variety of questions in Biology. We are interested in the signals cells exchange in order to control cell proliferation and differentiation during animal development. 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/MAPK and Notch pathways) controls the differentiation of vulval cells.
In one project, we are studying the C. elegans homologues of the human tumor suppressor genes. The APC gene is mutated in most cases of human colorectal cancer. In C. elegans, the APC gene is required for the transduction of a Wingless signal that specifies the identity and polarity of the vulval precursor cells, for the migration of epidermal cells in the embryo and for the correct segregation of chromosomes during mitosis.
In another project, we are investigating how negative regulators of RAS/MAPK signal transduction prevent the differentiation of excess cells during vulval development. In this context, we found that Notch induces several inhibitors of the RAS/MAPK signaling pathway, thus explaining the antagonism between the Notch and RAS/MAPK signaling pathways. In addition, we have identified new Notch target genes that mediate the cell type-specific functions of Notch.
More recently, we have initiated studies of the molecular mechanisms controlling the intracellular trafficking of growth factor receptors during cell fate specification.

Main Fields of Research, Keywords
Caenorhabditis elegans, signal transduction, developmental biology, tumor suppressor and onco-genes

Special Techniques and Equipment
Forward and reverse genetics, transgenics (all in C. elegans), high-throughput genotyping, high resolution micro-scopy, live imaging, laser microdissection, general molecular biology and biochemistry techniques

Education and Training
We have training opportunities for PhD and Masters students and for candidates of the Postgraduate Course of Medicine at the University of Zurich.