Fig. 1. Expression of HP1 and HP1 in various tissues and cell types. (A) Identification of HP1 and HP1 transcripts in human tissues by RT-PCR. Lanes: 1, endometrium; 2, myometrium; 3, mammary glands; 4, lymph nodes, 5, skin; L, a 1 kb DNA ladder. Sizes of amplified products (in bp) are indicated on the right. Beta-actin amplification was used as a control. For more details see Materials and Methods. (B,C) Immunocytochemical detection of HP1 and HP1 in (B) human epidermis, gastric mucosa, mammary gland and prostate, and (C) in mouse cerebellar cortex. Red arrows indicate Purkinje cells expressing both proteins. (D) Detection of the HP1 and HP1 proteins in human liver. Red arrows indicate Kupffer cells and black arrows, hepatocytes. (E) Staining of human liver with control (anti-lamin B and anti-me₂K4 histone H3) antibodies. In D and E the two upper panels show hepatic lobules, whereas lower panels show inter-lobular space containing bile ducts.