Overview of Research Program
In the Hill/Jackson-Hayes Lab

Principal Investigators

Terry W. Hill
Professor of Biology

Loretta Jackson-Hayes
Assoc. Prof. of Chemistry

Link to Former Research Associates

Background

Fungi are one of the most important groups of microorganisms.  Some, for instance, cause extensive damage to the world's food supply through their activities as crop pathogens, while others account for an increasing number of human infections, especially in immunocompromised patients.  Most, though, play essential and beneficial roles in nature, acting as recyclers of complex organic material, as nutritional symbionts of most plants and many animals, and in many other roles.  In addition, many fungi are used in important human economic activities like the production of foods, beverages, and biochemicals.

Cell growth and differentiation underlie all activities of the fungi. Our laboratory's work has focused mainly on the role that the cell wall plays in these processes.  A properly constructed cell wall is essential to establishing and maintaining the basic form and function of a fungus, especially in permitting fungal cells to adopt a filamentous ("hyphal") cell form, which enables them to invade and degrade organic materials.

An additional reason for studying fungal cell walls is the fact that the wall is the structure that most distinguishes the cells of fungi from the wall-less cells of animals.  Chemotherapeutic agents used to treat infections rely upon the principle of differential toxicity, which means that they interfere with a metabolic process that is of much more importance to the pathogen than it is to the host.  There already exist clinically useful antifungal compounds that inhibit aspects of cell wall metabolism (specifically chitin and glucan synthesis), which are not found in human metabolism.  Considering the complexity of cell wall composition and architecture, however, a thorough study of the wall is certain to uncover many new physiological processes unique to fungal metabolism, which may provide keys to the development of still further antifungal compounds.

Major Goals

The long-term goal of research in this laboratory is to understand how the structural components of fungal cell walls are synthesized, assembled according to specific patterns, and developmentally modified throughout the organism's life.  Through a better understanding of the cell wall we may discover keys to better control over growth of economically and medically important fungi.

Ongoing projects include the following:

Isolation and Characterization of Calcofluor-Hypersensitive Mutants   Our basic strategy for identifying potential cell wall mutants has been to screen mutant libraries for strains exhibiting hypersensitivity to the wall-compromising agent Calcofluor White (CFW).  This phenotype correlates with defects in wall integrity. We have designated loci whose mutations result in this property Cal genes (Hill et al., 2006.)  Click here for more information on our work with cal mutants.

Targeting of Protein Kinase C (PKC) to Sites of Polarized Cell Growth   The mutated locus in the CFW-hypersensitive calC2 mutation encodes an orthologue of PKC (designated PkcA), which we have localized to hyphal apices and to growing septa (Teepe et al., 2007).  Work is underway to identify the role of PkcA at these sites by expressing a PkcA::GFP chimera in strains that also carry mutations in other genes known to play roles in septation and tip growth, as well as by simultaneous imaging PkcA::GFP and other tagged proteins in living cells.  To see more of our results and continuing work on PkcA, click here.

A Plasma Membrane Protein Affecting Wall Integrity, Unique to Filamentous Fungi   In our work with PkcA, we discovered a multi-copy suppressor of the calC2 phenotype, which we term SccA (for Suppressor of CalC2).  SccA is predicted to be a serine-threonine-rich membrane protein. Go here for more information about SccA.

The Role of GDP-Mannose Transporters in Morphogenesis and Wall Integrity   We have identified two loci encoding GDP-mannose transporters (GMTs) by cloning the gene responsible for the CFW-hypersensitive and hyperbranching phenotype of the calI11 mutant strain. We designate these GmtA and GmtB (Jackson-Hayes et al., 2008; Jackson-Hayes et al., 2009).  Using a GmtA::GFP hybrid, we have provided evidence that GmtA is localized in a cis-like compartment of the fungal Golgi equivalent.  For more information on our published observations and ongoing work with A. nidulans GMTs, click here.

The Role of COG Proteins in Morphogenesis   The swoP1 mutation was discovered in a screen for temperature-sensitive morphological mutants in A. nidulans, and shows impaired polarization during spore germination at restrictive temperature.  The gene has been cloned and shown to be an orthologue of COG4, a component of the Golgi apparatus COG (Conserved Oligomeric Golgi) vesicle tethering complex.  More information about the COG project can be found here.

Undergraduate Research Opportunities

Students with strong research interests in cell biology, biochemistry, genetics, or microbiology
are encouraged to apply for positions in this lab.

Summer Research Fellowships

The National Science Foundation

What do students in our lab do?


Click here to find out

Summer Research Fellowships

Funded by
Merck/AAAS

Research Students, Summer 2012
Kristen, Brianna, Taylor, Xiao

For information on current and former student lab members, click here.

Link to Hill Homepage

Link to Jackson-Hayes Homepage