Gel Electrophoretic Analysis of Histones in Lens Epithelium, Lens Fiber, Liver, Brain, and Erythrocytes of Late Chick Embryos

Abstract

Histones from 19-day-old chick embryo lens epithelium, lens fibers, liver, brain, and erythrocytes were electrophoresed in polyacrylamide gels using buffers containing sodium dodecylsulfate, acetic acid urea, or mixtures of Triton X-100 acetic acid urea. In the last two buffer systems, histone bands were characterized by their apparent molecular weights determined by electrophoresis in the second dimension in sodium dodecylsulfate containing polyacrylamide gels. From the densitograms of the stained gels, the relative proportion of protein in different histone bands was estimated. With the exception of the erythrocyte-specific histone H5, all histones from different tissues examined at any of the gel systems migrated with the same mobilities. In lens epithelium and lens fibers, all histones were present in identical proportions. As compared to liver and brain, the total amount of histone Hl was significantly lower in lens cells and erythrocytes, possibly reflecting differences between the differentiated states. However, no tissue-specific differences were found in the relative distribution of histone Hl I and Hl II among lens epithelium, lens fiber, liver and, brain, but a threefold higher Hl I : Hl II ratio (0.5--0.7) was found in erythrocytes.