Histone 'dynamics' revealed by photoconverting expressed Dendra2-H2B. Entire cell nuclei (in A, and top row in B), or portions of nuclei (center and bottom rows in B) of Dendra2-H2B expressing HeLa cells were photoconverted within 5-10 sec (circled areas), and green and red channels were imaged immediately after photoconversion (in A), and after 1-hour (in B). One-hour post conversion, the areas of photoconverted histone H2B protein and the edges between photoconverted and unconverted Dendra2-H2B domains were still well defined, revealing H2B's stable association with DNA in interphase chromatin. DIC and fluorescence images were merged in (A) to reveal the location of cell nuclei, and transiently transfected Dendra2-H2B expressing cells. Note that more or less efficient photoconversion of cell nuclei was achieved (compare remaining green fluorescence in the circled areas in B, rows 1 and 3, compared with row 2).