Project Overview
Genetic Regulation of Biofilm Formation in Agrobacterium tumefaciens
Department(s)
Biology
Abstract
Dr. Greenwich’s research focuses on the plant pathogen Agrobacterium tumefaciens and how it forms communities known as biofilms to attach to surfaces. Many bacteria form biofilms, and they are a common cause of infections. Importantly, the processes by which A. tumefaciens attach to surfaces are conserved across numerous human and animal pathogens. Agrobacterium uses a polysaccharide called the unipolar polysaccharide (UPP) to attach. The research focuses specifically on the bacterial second messenger cyclic-di-guanylate monophosphate (cyclic-di-GMP, or cdGMP), which is known to regulate surface attachment and biofilm formation. Elevated levels of cdGMP promote attachment, while low levels trigger a planktonic life cycle. cdGMP is synthesized by enzymes known as diguanylate cyclases (DGCs) and degraded by phosphodiesterases (PDEs). In A. tumefaciens, a dual function enzyme known as DcpA can perform both activities and is critical for production of the UPP. DcpA is regulated by a small protein encoded upstream of it known as PruR, which interacts with DcpA to promote the PDE activity under standard laboratory conditions.
The proposed projects focus on identifying the amino acid residues important for the interaction of DcpA with itself as well as with PruR. DcpA must dimerize to function as either a DGC or PDE. The first project will focus on identifying residues in DcpA required for it to dimerize to function as a DCG, and the second will focus on identifying residues in DcpA as well as PruR that are important for their interaction. Both projects will use a variety of genetic techniques including site-directed and random mutagenesis as well as biochemical techniques of western blotting. Molecular cloning will also be involved in both projects. Students will be expected to work with each other as well as myself and aid in the design and analysis of experiments. Dr. Greenwich will provide all necessary training in the lab.
Student Qualifications
Interested students should have successfully completed BIOL182 (or similar) to be familiar with the terminology and biological concepts involved in the research.
Number of Student Researchers
2 students
Project Length
10 weeks
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