Hasegawa Shinya, Imai Masahiko, Yamasaki Masahiro, Takahashi Noriko, Fukui Tetsuya
Department of Health Chemistry, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan.
Department of Health Chemistry, Hoshi University, Shinagawa, Tokyo, 142-8501, Japan.
Biochem Biophys Res Commun. 2018 Jan 1;495(1):652-658. doi: 10.1016/j.bbrc.2017.11.068. Epub 2017 Nov 11.
Acetoacetyl-CoA synthetase (AACS) is the enzyme responsible for cholesterol and fatty acid synthesis in the cytosol. We have previously shown that AACS has an important role in normal neuronal development and that knockdown of SREBP-2, which orchestrates cholesterol synthesis, resulted in the downregulation of AACS mRNA levels. In this study, we investigated the transcriptional mechanism of AACS in Neuro-2a, neuroblastoma cells. Luciferase assay showed that the minimal core promoter of the mouse AACS gene is located in a region with 110 bps upstream from the transcription start site. Mutagenesis studies showed that the Sp1 binding site was crucial for AACS promoter activity. ChIP assay and DNA affinity precipitation assay showed that Sp1 binds to the Sp1 binding site on the promoter region of AACS. Moreover, overexpression of Sp1 increased AACS mRNA levels. Knockdown of AACS resulted in a decrease in histone deacetylase 9, associated with gene silencing. These results suggest that Sp1 regulates gene expression of AACS in Neuro-2a cells and ketone body utilization affects the balance of histone acetylation.
乙酰乙酰辅酶A合成酶（AACS）是负责胞质溶胶中胆固醇和脂肪酸合成的酶。我们之前已经表明，AACS在正常神经元发育中具有重要作用，并且协调胆固醇合成的SREBP-2的敲低导致AACS mRNA水平下调。在本研究中，我们研究了神经母细胞瘤细胞Neuro-2a中AACS的转录机制。荧光素酶测定表明，小鼠AACS基因的最小核心启动子位于转录起始位点上游110个碱基对的区域。诱变研究表明，Sp1结合位点对AACS启动子活性至关重要。染色质免疫沉淀测定和DNA亲和沉淀测定表明，Sp1与AACS启动子区域的Sp1结合位点结合。此外，Sp1的过表达增加了AACS mRNA水平。AACS的敲低导致组蛋白脱乙酰酶9减少，这与基因沉默有关。这些结果表明，Sp1调节Neuro-2a细胞中AACS的基因表达，并且酮体利用影响组蛋白乙酰化的平衡。
