Flow cytometry of μ expression from reporter gene bearing different segments of the full enhancer.

<div><p>Transfectants bearing the indicated reporter genes were analyzed by flow cytometry. </p> <p>Cells were fixed and permeabilized, and intracellular μ chains were stained with μ-specific fluorescent antibodies.</p> <p>∼10⁴ cells were then analyzed.</p> <p>In these histograms the horizontal axis indicates the mean fluorescence (logarithmic scale) and the vertical axis the number of cells with the corresponding fluorescence. M is the mean fluorescence for each population.</p> <p>Z10/HyTK, the recipient cell line was used in this case as the negative control, and its mean “fluorescence”, M₀, for each experiment was subtracted from the mean fluorescence, M_x, measured for a cell population expressing reporter “x”.</p> <p>This corrected fluorescence is compared with M₆₂₆, the corrected fluorescence in that experiment for the reporter #626 with the full enhancer.</p> <p>Thus, the “normalized” fluorescence, N_x, for reporter “x” was calculated as N_x = (M_x−M₀)/(M₆₂₆−M₀), where M₆₂₆ is the mean fluorescence for the reporter with the full enhancer and M₀ is the fluorescence for the recipient cell line or other μ non-expresser.</p> <p>σ is the standard deviation of the fluorescence. In order to correct for variation in background “fluorescence”, we calculated a corrected coefficient of variation, C_x, for reporter “x” as C_x = (σ_x²−σ₀²)^1/2/M_x−M₀, where σ_x and σ₀ are the standard deviations associated, respectively, with reporter “x” and with the recipient cell line or other μ non-expresser.</p>