Exploring the emerging properties of novel GFP-like fluorescent proteins

In 2008 the Nobel Prize in Chemistry was awarded to the scientists who revolutionized biomedical technology by isolating, characterizing, and pioneering the use of a green fluorescent protein (GFP) from a humble hydrozoan jellyfish. Now numbering in the hundreds of colors and applications, fluorescent protein (FP) tools have facilitated the explosion of biological knowledge elucidated by a technology that can label DNA or RNA, track protein expression, and identify protein interactions. The development of the large variety of FP biotechnology available today has been due to the need for expanded color palettes and applications, and more efficient functionality. Yet, as our understanding of the biochemical and spectral characteristics of these genetically-encoded, self-assembling proteins has expanded, our comprehension of the biological function of FPs in the host organisms has remained inadequate. While the need for novel FP laboratory applications still continues, the new focus in the field of fluorescent proteins is moving to also characterize their biological functions. In this research compilation, the identification of three groups of new fluorescent proteins from marine copepods and hydrozoans has provided a collection of eleven FPs exhibiting previously uncharacterized colors, and biochemical and structural features. The green FPs from copepods are the brightest wild-type FPs identified and support the hypothesized biological function of fluorescence as counter-shading in the marine environment where these animals live. The FPs from the siphonophore and anthoathecate jelly, both hydrozoan animals, are comprised of tandemly expressed fluorescent protein units, a solution to the oligomeric structure common to most FPs that suggests a novel structure-function relationship. The fluorescent proteins from Obelia reveal a novel hydrozoan cyan FP, previously uncharacterized higher-order structural complexes, and have initiated the work to describe the biological function of these proteins as potential regenerators of their internal bioluminescent light sources. All eleven fluorescent proteins may also be adapted for FP technology.