A thymocyte factor SATB1 suppresses transcription of stably integrated matrix-attachment region-linked reporter genes
A thymocyte factor SATB1 suppresses transcription of stably integrated matrix-attachment region-linked reporter genes
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DOI：
10.1021/bi971444j
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发表时间：
1997-10-07
期刊：
影响因子：
2.9
通讯作者：
Bode, J
中科院分区：
文献类型：
--
作者：
KohwiShigematsu, T;Maass, K;Bode, J
SATE 1特异性识别并结合具有高碱基解配对倾向的ATC序列背景的特定基因组区域。这种碱基不配对区（布尔斯）通常在核支架或基质附着区（S/MAR）内鉴定。SATB 1是一种同源结构域蛋白，主要在胸腺细胞中表达。我们通过稳定转染获得了低水平表达SATE 1的BHK细胞系，并研究了其对稳定整合的MAR连接的SV 40增强子/启动子驱动的荧光素酶报告基因的影响。对于本研究，测试了天然存在的和合成的MAR以及富含AT的非MAR对照。先前的研究表明，MAR序列增加了连接的报告基因荧光素酶基因的转录。在这里，我们表明，SATE 1显着降低MAR连接的荧光素酶基因转录的高水平。对于在基因的5'和3'末端被两个MAR包围的报告基因，转录实际上被废除，否则其赋予最高水平的转录增强。另一方面，SATB 1不影响AT丰富的非MAR连接的荧光素酶基因或内源性管家基因的表达。这项研究表明，SATE 1作为一个强大的转录抑制报告基因连接到MAR时，它是稳定整合到染色质。
SATE1 specifically recognizes and binds to specialized genomic regions with an ATC sequence context with high base-unpairing propensity. Such base-unpairing regions (BURs) are typically identified within nuclear scaffold-or matrix-attachment regions (S/MARs). SATB1 is a homeodomain protein and is predominantly expressed in thymocytes. We obtained BHK cell lines expressing low levels of SATE1 by stable transfection and investigated its effect on stably integrated MAR-linked SV40 enhancer/promoter-driven luciferase reporter genes. For this study, both naturally occurring and synthetic MARs, as well as an AT-rich non-MAR control, were tested. Previous studies demonstrated that MAR sequences augment transcription of the linked reporter luciferase gene. Here, we show that SATE1 dramatically reduces the high levels of MAR-linked luciferase gene transcription. Transcription was virtually abolished for a reporter gene surrounded by two MARs at the 5' and 3' ends of the gene, which otherwise confer the highest level of transcriptional augmentation. On the other hand, SATB1 did not affect expression of an AT-rich non-MAR-linked luciferase gene or of endogenous housekeeping genes. This study shows that SATE1 acts as a strong transcriptional suppressor on a reporter gene linked to MARs when it is stably integrated into chromatin.