FIG. 4.

Cleavage of C/EBPβ occurs in the liver before birth. (A) Densitometric analysis showing that cleavage is activated in the livers of C/EBPα wild-type (+/+) mice at the following times during development: 16 days of gestation (16 d), 18 days of gestation (18 d), and newborn animals (newb). No cleavage was detected in C/EBPα null (−/−) livers. The graph represents an average of three independent experiments. NE, nuclear extract. (B) Representative example of a C/EBPβ cleavage assay with tissues from wild-type mice at the same times during development. The positions of LAP, C-LIP, and C-13 are shown. N, newborn animals; KO, C/EBPα null extracts.