FIG. 9.

Transcriptional repression by the HP1α CSD is correlated with its ability to bind KAP-1. Three independent transfections were conducted with plasmids (5 μg) expressing G4DBD fusions to human HP1α CSD mutants, and fold repression was calculated as described in the legend to Fig. 8. Asterisks indicate mutants that displayed little or no repression activity, as evidenced by analysis with G4DBD alone. The bottom panel shows the results of an anti-G4DBD immunoprecipitation from a duplicate transfection series in which cells were metabolically labeled with [³⁵S]methionine. The large arrow marks the CSD fusion protein, and the small arrow marks G4DBD alone. wt, wild type.