[Expression of BCL-2 protein in tissues and organs of the human embryo]

The bcl-2 gene product is a 24-kD protein localized in the nuclear envelope, endoplasmic reticulum, and mitochondrial membranes. Protein BCL-2 prolongs survival cells by blocking programmed cell death--apoptosis. The role of this protein in the regulation of mammalian embryo development is also suggested. BCL-2 is widely expressed early in mouse fetal development in tissue derived from all three germ layers and this expression becomes restricted with maturation. The expression of BCL-2 was studied in 20 human embryos from the 4 to 12 weeks gestation. Immunoperoxidase staining was performed using the mouse primary monoclonal antibody clone 124 (Dako, Danmark). We found the expression of BCL-2 in many organs of gastrointestinal tract, in mesenchymal cells surrounding primitive bronchial epithelium, in the cells of the metanephronic blasteme and ureteric buds. Our results indicate that bcl-2 gene could play an important role in the human embryonal tissue development.