Bait expressed and purified from bacteria.

Prey endogenous to cells and purified as mononucleosomes.

HP1c-bound His3 is enriched for K9 trimethylation.

GST pull down.

Bait expressed and purified from bacteria.

Prey endogenous to cells and purified as total nucleosomes.

HP1c binds His3 purified from S2 cells, but not recombinant His3.

A His3 N-terminal peptide bearing K9 trimethylation, but not unmodified peptide, competes with endogenous His3 for binding to HP1c.

Purified HP1c was fractionated by PAGE, transferred to membrane, and tested for its ability to bind endogenous His3. Binding was assayed using anti-His3 antibodies.

Bait endogenous to cells and purified as nucleosomes.

Prey expressed and purified from bacteria.

Purified His3 was fractionated by PAGE, transferred to membrane, and tested for its ability to bind HP1c.

Interaction in vitro; recombinant proteins produced in baculovirus and insect cell system.

Interaction detected with H3K9me2 and H3K9me3 not with H3K4me2 or H3K36me3

For HP1c-His3K9me3, Kd = 5.6uM

Interaction in vitro; bait produced as a recombinant fusion protein in bacterial or baculoviral system; prey peptide chemically synthesized and labeled in vitro.