FIG. 2.

Epitope-tagged MSL2 colocalizes with MOF and histone H4 acetylated at lysine 16 (H4Ac16) on the X chromosome in S2 cells. (A) Cells were transfected with a construct expressing MSL2 fused to the HA epitope. Tagged MSL2 is detected with the 12CA5 monoclonal antibody, while endogenous MOF is detected with a rabbit polyclonal antibody to the C terminus of MOF. The top panel shows that a small fraction of the cells contain transfected MSL2-HA, which is seen colocalizing with endogenous MOF. The bottom panel shows an enlargement of a nucleus where both antibodies can be seen painting a chromosome that traverses the nucleus. (B) Stable cell lines were selected with hygromycin, and a line that expressed a low level of basal (uninduced) expression was chosen for further study. In this line, basal levels of MSL2-HA can be detected along the length of the X chromosome, coincident with H4Ac16 and the other MSLs (not shown). Occasional areas of nonoverlap may reflect the presence of partial or nonfunctional complexes.