Figure 5.

The pattern of histone H4 acetylation across the murine α-globin locus in mouse erythroleukemia cells. (a) Above, the structure of the murine locus is set out as previously described (15). The globin genes are annotated, and other orthologous genes correspond to the human genes set out in Fig. 1 (e.g., murine no. 7 is the orthologue of human no. 7). The probes used to establish the patterns of core histone acetylation across the murine αglobin cluster are described in Table 1. The scale is in kilobases. The asterisk denotes a hypersensitive site that is assumed to be present but has not been experimentally demonstrated. Acetylation of the core histone H4 at Lys-16 (white boxes and dashed line) and Lys-5 (black circles and black line) is shown. The levels of acetylation for other N-terminal tail lysines are displayed in Fig. 7. Levels of acetylation at control loci were established independently for each experiment and include the α-tubulin genes (T) and a probe (het 947) to heterochromatin repeat sequences (H). (b) The levels of acetylation of Lys-5 and Lys-16 across the putative 3′ boundary were assessed in seven entirely independent experiments. The results obtained with a probe (m8: 123,063–124,463 and 135,985–137,367) to the α-globin gene are shown as a diagonally striped box and those by using a probe beyond the putative boundary (m9: 141886–142293) as a vertically striped box. Vertical lines indicate ±1 SD.