We are using the filamentous fungus Neurospora crassa as a model organism to study cell biology. In particular, we are interested in cell-to-cell signaling and fusion in eukaryotes. During colony establishment, germinating spores of N. crassa mutually attract each other, establish physical contact and undergo cell fusion (see movie below). A combination of live-cell imaging and molecular genetic analysis revealed an unusual mode of cell-cell signaling controlling this interaction. During directed growth, the MAP kinase MAK-2 localizes to the cell tips of interacting germlings in a highly dynamic, oscillatory manner (see time course below). We hypothesize that the cells undergo some kind of "cell dialog", in which both partners alternate between signal sending and signal receiving. To further understand the molecular basis mediating intercellular communication and fusion, we analyze the behavior of knock-out mutants affected in genes required for this process. By means of fluorescence microscopy, we look at the subcellular localization of proteins during germling fusion and, thus, can explore their function within the cells. These studies will extend our knowledge about cell-cell signaling in filamentous fungi and, more general, in eukaryotic organisms.
Filamentous fungi are widely used as protein production hosts in various biotechnological applications. Productivity of such processes is strongly influenced by the morphology of the fungus. In liquid culture, filamentous fungi can grow as mycelial suspensions, in small aggregates, so called pellets, or as biofilms. We use Aspergillus niger, one of the most important production organisms, to study the molecular basis of fungal morphogenesis and differentiation.
In addition, we are trying to establish the red bread mold Neurospora crassa, as a production host for heterologous proteins. While Neurospora has been a genetic model organism for many years, its potential for biotechnological application is mostly untapped. Its experimental tractability and the availability of a huge collection of classical and knock-out mutants, offer much promise for innovative production processes.