Fig. 4. Loss of HP1s from chicken erythrocytes. (A) Western blot of mouse 3T3, chicken DT40 and adult chicken erythrocyte nuclear proteins with antibodies detecting HP1 isoforms, di- (met2H3-K9) and tri- (met3H3-K9) methylated H3 K9, and H3 methylated at K4 and K27. Antibody detecting H3 is used as a control. (B) Quantification of HP1α, met2H3-K4, met3H3-K9 and met3H3-K27 levels in mouse, DT40 and chicken erythrocyte nuclei. Signals were normalized with respect to total histone H3. (C) Coomassie-stained gel of mouse 3T3, chicken DT40, chicken day 10 embryonic erythrocytes and adult chicken erythrocytes. Histone H5 is indicated by an arrow. Western blots of equivalent samples probed with antibodies against H5 and HP1α are shown below.