{'fraction_non_alphanumeric': 0.03414028553693358, 'fraction_numerical': 0.004345127250155183, 'mean_word_length': 5.371541501976284, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Control of adipocyte differentiation by CCAAT/enhancer binding proteinα (C/EBPα)

Upon differentiation of 3T3-L1 preadipocytes into adipocytes transcription of many adipose-specific genes is coordinately activated. A differentiation-induced factor, later identified as C/EBPα, binds to and transactivates the promoters of these genes. Vector-directed expression of antisense C/EBPα RNA in preadipocytes blocked expression of C/EBPα, as well as adipose-specific mRNAs, and also prevented cytoplasmic triglyceride accumulation. Rescue of the 'adipocyte phenotype' was accomplished by transfection of the antisense cells with a complementary sense C/EBPα RNA expression vector. Using an IPTG-inducible double-vector LacSwitch C/EBPα expression system, it was found that differentiation can be induced without exogenous hormone inducers. These findings indicate that C/EBPα is not only required, but is sufficient, to trigger differentiation of 3T3-L1 preadipocytes. The C/EBPα gene promoter possesses a C/EBP binding site through which C/EBPα autoactivates its own expression. A nuclear protein referred to as CUP (C/EBP undifferentiated protein) that binds to a bipartite element in the C/EBPα promoter just 5' to the C/EBP binding site has been purified and characterized. During differentiation of preadipocytes, expression of CUP activity decreases as expression of C/EBPα increases. Evidence suggests that a CUP-containing protein complex bridges between the CUP (repression) and C/EBP (autoactivation) elements in the promoter and may maintain the C/EBPα gene in the repressed state prior to differentiation.