He G P, Muise A, Li A W, Ro H S
Department of Biochemistry, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
Nature. 1995 Nov 2;378(6552):92-6. doi: 10.1038/378092a0.
Adipocyte differentiation involves the transcriptional activation of several genes in triglyceride metabolism, including the adipose P2 (aP2 or 422) gene that encodes the adipocyte lipid-binding protein ALBP. Within the mouse aP2 promoter region, the AE-1 sequence functions as either a positive or a negative element in the regulation of aP2 gene expression. The AE-1 sequence is the binding site for the positive murine (3T3) adipocyte factor C/EBP-alpha, several human preadipocyte factors, and a 3T3 preadipocyte factor(s) that has been implicated as a repressor of aP2 gene expression. Here we report the cloning of new complementary DNAs that encode the 3T3 preadipocyte factor (termed AEBP1) and demonstrate that AEBP1 expression is abolished during adipocyte differentiation. Furthermore, we show that an activity of a carboxypeptidase associated with AEBP1 is important in the transcriptional repression function of AEBP1. Thus AEBP1 might represent a new type of transcription factor that regulates transcription by cleavage of factors involved in transcription.
脂肪细胞分化涉及甘油三酯代谢中多个基因的转录激活，包括编码脂肪细胞脂质结合蛋白ALBP的脂肪P2（aP2或422）基因。在小鼠aP2启动子区域内，AE-1序列在aP2基因表达调控中既作为正调控元件也作为负调控元件发挥作用。AE-1序列是正向鼠（3T3）脂肪细胞因子C/EBP-α、几种人前脂肪细胞因子以及一种被认为是aP2基因表达阻遏物的3T3前脂肪细胞因子的结合位点。在此，我们报告了编码3T3前脂肪细胞因子（称为AEBP1）的新互补DNA的克隆，并证明AEBP1的表达在脂肪细胞分化过程中被消除。此外，我们表明与AEBP1相关的一种羧肽酶活性在AEBP1的转录抑制功能中很重要。因此，AEBP1可能代表一种新型转录因子，它通过切割参与转录的因子来调节转录。
