Sabatakos G, Davies G E, Grosse M, Cryer A, Ramji D P
School of Molecular and Medical Biosciences, University of Wales Cardiff, P.O. Box 911, Cardiff CF1 3US, U.K.
Biochem J. 1998 Aug 15;334 ( Pt 1)(Pt 1):205-10. doi: 10.1042/bj3340205.
Transcription factors belonging to the CCAAT-enhancer binding protein (C/EBP) family have been implicated in the activation of gene expression in the mammary gland during lactation. We have therefore investigated the detailed expression profile of the C/EBP family during lactation and involution of the mouse mammary gland. The expression of C/EBPbeta and C/EBPdelta mRNA was low during lactation, increased dramatically at the beginning of involution and remained constant thereafter. In contrast, C/EBPalpha mRNA expression was relatively high during the early stages of lactation, declined to low levels during the late stages of lactation and at the start of involution, and increased again during involution. Electrophoretic mobility-shift assays showed a close correlation between the expression of the C/EBP genes and the functional C/EBP DNA-binding activity and, additionally, demonstrated the participation of heterodimers, formed from among the three proteins, in DNA-protein interactions. The DNA-binding activity of the activator protein 1 (AP1) family of transcription factors was also induced during involution. These results therefore point to potentially important regulatory roles for both the C/EBP and the AP1 family during lactation and involution of the mammary gland.
属于CCAAT增强子结合蛋白（C/EBP）家族的转录因子与泌乳期间乳腺中基因表达的激活有关。因此，我们研究了小鼠乳腺泌乳和退化过程中C/EBP家族的详细表达谱。C/EBPβ和C/EBPδ mRNA在泌乳期间表达较低，在退化开始时急剧增加，此后保持恒定。相比之下，C/EBPα mRNA表达在泌乳早期相对较高，在泌乳后期和退化开始时降至低水平，并在退化期间再次增加。电泳迁移率变动分析表明，C/EBP基因的表达与功能性C/EBP DNA结合活性密切相关，此外，还证明了由这三种蛋白质形成的异二聚体参与了DNA-蛋白质相互作用。转录因子激活蛋白1（AP1）家族的DNA结合活性在退化过程中也被诱导。因此，这些结果表明C/EBP和AP1家族在乳腺泌乳和退化过程中可能具有重要的调节作用。
