Bcl-2 protein expression during murine development.
Bcl-2 functions as a death repressor molecule in an evolutionarily conserved cell death pathway. To further explore the role of Bcl-2 in development, we assessed its pattern of expression during murine embryogenesis. Immunohistochemical analysis demonstrates that Bcl-2 is widely expressed early in mouse fetal development in tissues derived from all three germ layers and that this expression becomes restricted with maturation. Within epithelium, the E12.5 lung bud demonstrates a proximal to distal gradient of Bcl-2 expression which is enhanced by E18.5. Bcl-2 is expressed throughout the intestinal epithelium through E14.5, but by E18.5 only cells in the crypts and lower villi express Bcl-2. In the mesoderm-derived kidney, Bcl-2 is expressed in both the ureteric bud and metanephric cap tissue at E12.5. Tubular structures also express Bcl-2, although overall levels drop as the kidney matures. Retinal neuroepithelial cells uniformly express Bcl-2 until cells begin to differentiate and then display the topographic distribution maintained into adulthood. The developing limb provides a clear example where Bcl-2 is restricted to zones of cell survival; Bcl-2 is expressed in the digital zones but not in the interdigital zones of cell death. The wide distribution of Bcl-2 in the developing mouse suggests that many immature cells require a death repressor molecule or that Bcl-2 may have roles beyond regulating developmental cell death.
Novack
D V
DV
Department of Medicine, Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, Missouri 63110.
Korsmeyer
S J
SJ
D000818:Animals; D001923:Brain Chemistry; D004622:Embryo, Mammalian / Q000737:chemistry*; D005314:Embryonic and Fetal Development; D004848:Epithelium / Q000737:chemistry; D005121:Extremities / Q000196:embryology; D007421:Intestine, Small / Q000737:chemistry / Q000196:embryology; D007668:Kidney / Q000737:chemistry / Q000196:embryology; D008099:Liver / Q000737:chemistry / Q000196:embryology; D008168:Lung / Q000737:chemistry / Q000196:embryology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D019253:Proto-Oncogene Proteins c-bcl-2; D012679:Sense Organs / Q000737:chemistry
D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2