FIG. 5.

Histone acetylation profiles at the hCD79b/GH locus in B-cell chromatin are predominantly localized to the area of CD79b. A. Diagram of the hCD79b/GH locus. The position of each amplimer set used in the chromatin immunoprecipitation (ChIP) analysis is indicated below the diagram (labeled dashes). B. Patterns of histone H3 and H4 acetylation throughout the human hCD79b/GH region in a B-cell line expressing high levels of CD79b mRNA. Chromatin from line 1484 was used as a representative high-expressing line (Fig. 1B). DNAs isolated from anti-acetyl H3 and anti-acetyl H4 ChIPs were amplified with the indicated primer sets and normalized (described in Materials and Methods). Each histone modification value was calculated as the ratio of DNA in the antibody-bound chromatin to that in the input sample. Mean histone H3 acetylation (dark bars) and histone H4 acetylation (light bars) are plotted. The amplimer regions analyzed are indicated underneath each pair of bars. The means ± standard deviations are representations of a minimum of two independent assays. C. Patterns of histone H3 and H3 acetylation in a plasma cell line with low levels of CD79b. U266 was selected as a representative B-cell line expressing trace levels of CD79b mRNA (Fig. 1B). Analyses and labeling are as described for panel B. D. Patterns of histone H3 and H4 acetylation in an erythroid cell line. The K562 erythroleukemia line does not express CD79b mRNA (Fig. 1B). E. Patterns of histone H3 and H4 acetylation in splenic B cells expressing hCD79b from an hGH/P1 transgenic mouse (line 811D). F. Patterns of histone H3 and H4 acetylation in liver tissue from the same hGH/P1 transgenic mouse used in the experiment depicted in panel E (line 811D).