Qq. Tang et Md. Lane, Activation and centromeric localization of CCAAT/enhancer-binding proteinsduring the mitotic clonal expansion of adipocyte differentiation, GENE DEV, 13(17), 1999, pp. 2231-2241
Hormonal induction of 3T3-L1 preadipocytes triggers a cascade of events tha
t initiate differentiation into adipocytes. CCAAT/enhancer-binding proteins
beta and delta (C/EBP beta/delta) are expressed early in the differentiati
on program, but are not immediately active. After a long lag, C/EBP beta/de
lta become competent to bind to the C/EBP regulatory element in the C/EBP a
lpha gene promoter, C/EBP alpha being a transcriptional activator of numero
us adipocyte genes. As C/EBP beta/delta acquire binding activity, they beco
me localized to centromeres as preadipocytes synchronously enter S phase at
the onset of mitotic clonal expansion. Localization to centromeres occurs
through C/EBP consensus-binding sites in centromeric satellite DNA. C/EBP a
lpha, which is antimitotic, becomes centromere-associated much later in the
differentiation program as mitotic clonal expansion ceases and the cells b
ecome terminally differentiated.