Figure 1.

p28 is specific to somatic macronuclei and missing from germ-line micronuclei. Total macronuclear proteins (T, lane 1), PCA soluble (S, lane 2), and insoluble (I, lane 3) proteins from equivalent amount of macronuclei and RP-HPLC-purified p28 (RP, see arrow in lane 4) were electrophoresed in a 12% SDS gel and either stained with Coomassie (A) or were blotted onto nitrocellulose and reacted with α-p28 (Hhp1p) antibodies followed by detection with AP (B, lanes 1–4). As well, comparable loads of acid-soluble micro- (lane 5) and macronuclear (lane 6) proteins, from unit gravity-purified nuclei, were subjected to a similar analyses except that enhanced chemiluminesence was used for detection (B, lanes 5–6,). The position of linker histone H1 and core histones is indicated by brackets (A); arrows denote p28 (A and B). Vegetatively growing cells also were fixed and incubated with p28 (Hhp1p) antibodies. In situ reactions were detected indirectly with rhodamine-conjugated secondary antibodies (C); nuclei in the same cells were detected with 4′,6-diamidino-2-phenylindole (D). A close inspection of p28 (Hhp1p) staining was taken by using confocal microscopy (E). White arrows point to micronuclei, that are consistently not stained with HHP1p antibodies.