Human Osteosarcoma with mEmerald-MAP4 and mApple-H2B
H2B is one of the 5 major histone proteins involved in the chromatin structure of eukaryotic cells. H2B features a central globular domain and a long N-terminal tail, and is engaged with the structure of the nucleosome of the 'beaded string' structure. The intracellular microtubule network and the cell nucleus are clearly visible in this digital video sequence due to fluorescent labeling of cultured human osteosarcoma cells (U-2 line) with mEmerald fused to MAP4 and mApple fused to H2B.
The green fluorescent protein mEmerald is a variant of EGFP, an enhanced Aequorea derivative. Excitation and emission of mEmerald peak at 487 and 509 nanometers, respectively. The fluorescent protein fused to H2B, mApple, is a red fluorescent protein that matures rapidly and is bright and photostable. mApple was developed from the results of a team led by Roger Tsien that successfully identified red fluorescent protein variants with improved photostability through a novel screening process. Excitation and emission of mApple peaks at 568 and 592 nanometers, respectively.