Description:

The Department of Biochemistry and Molecular Genetics Departmental Seminar Series presents:

Nathan C. Shaner, PhD
Assistant Professor
Scintillon Institute for Biomedical and Bioenergy Research, San Diego, CA

Since the advent of molecular cloning and recombinant DNA technology, fluorescent proteins (FPs) have made arguably the most significant impact on biological research of any technology in recent history. The most widely studied and exploited class of FPs by far has been those related to avGFP, which are characterized by intrinsic chromophores generated by autocatalytic peptide backbone cyclization and embedded within a compact β-barrel fold. FPs from this family are found in a wide range of marine invertebrates including jellyfish, corals, anemones, copepods, and lancelets. These proteins function as self-contained fluorophores that can be readily expressed in practically any heterologous organism, and can be genetically fused to a protein of interest to track its localization in living cells. Over the decades since the discovery of GFP in the jellyfish Aequorea victoria, FPs with excitation and emission wavelengths spanning virtually the entire visible spectrum have been cloned and engineered. In addition to traditional fluorescence imaging of living cells, novel techniques such as optical superresolution imaging take advantage of unique optical properties of specialized FP variants such as photoactivation, photoconversion, and photoswitching. Researchers around the world have cloned hundreds of wild-type FPs spanning most of the visible spectrum, and thousands more are likely awaiting discovery. Despite this, all FPs commonly used for imaging purposes in the laboratory are derived from only a handful of species. Our current research focuses on expanding the base from which to engineer useful new FP variants, including those with properties optimized for live-cell superresolution imaging. Investigations into the structure of some of these newly-cloned FPs are helping to guide the development of these new genetically encoded tools.