Genetic and Molecular Dissection of Hyphal Anastomosis

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Filamentous fungi grow by tip extension, branching and hyphal fusion to form a hyphal network that makes up a fungal individual. Some fungal colonies are microscopic, while others can be acres in size. Although tip growth and branching have been extensively studied in filamentous fungi, little is known about the mechanism of hyphal fusion or the function of the formation of a hyphal network. Previous studies on the hyphal fusion process by live cell imaging and confocal microscopy in the filamentous fungus, Neurospora crassa, have revealed a complex and carefully regulated biological process with obvious consequences to the fungal individual. Hyphal anastomosis is a way to increase cytoplasmic flow and interconnectedness of hypha, which may be important in intra-hyphal communication that influences hyphal pattern formation and developmental processes. Hyphal fusion in filamentous fungi is comparable to cell fusion events in other organisms, such as fertilization events between egg and sperm and somatic cell fusion events that result in syncytia, such as myoblast fusion during muscle differentiation and between osteoclasts during bone formation. The identification of hyphal anastomosis mutants in filamentous fungi will provide information and tools by which to genetically and molecularly characterize the signaling aspects and the machinery of the fusion process, in addition to illuminating the phenotypic consequences to the fungal individual of the inability to form a hyphal network. The studies will be performed on Neurospora crassa because of its tractability for live cell imaging techniques, full genome sequence information, the ease of genetic and molecular techniques and the positive interactions of the Neurospora community. The goal is to dissect the process of hyphal fusion by using a combination of live cell imaging, genetic analysis and biochemical tools to elucidate the mechanisms of self-signaling, polarization and fusion. Broader Impacts: Students at various levels will be involved in this project and they will learn a variety of techniques in genetics, cell imaging, genomics and molecular biology. Students from underrepresented groups will be supported through a summer internship program.