Adachi K, Katsuyama M, Song S, Oka T
Laboratory of Genetics and Physiology, Room 106, Building 8, National Institutes of Diabetes, Digestive and Kidney Disease, National Institutes of Health, Bethesda, MD 20892, USA.
Biochem J. 2000 Feb 15;346 Pt 1(Pt 1):45-51.
mStaf is a zinc-finger protein that activates the transcription of the mouse selenocysteine tRNA gene. The mStaf gene is approx. 35 kb long and split into 16 exons. All exon-intron junction sequences conform to the GT/AG rule. The transcription start site is located 83 bp upstream of the initiation codon. Chromosomal mapping localized the gene to mouse chromosome 7, region E3-F1. Sequence analysis of the proximal promoter region revealed several potential regulatory elements; these include the recognition elements of Sp1, Nkx, CP2, E2A, SIF (SIS-inducible factor), TFII-I and cAMP-responsive element (CRE), but no TATA sequences. Transfection experiments demonstrated that the 5'-flanking region (-1894 to +37) of the mStaf gene drives transcription in mouse NMuMG cells and that a construct containing a fragment from -387 to +37 showed the highest transcriptional activity. Deletion and mutation experiments suggested that four Sp1 sites played an important role for the basal promoter activity. Furthermore, electrophoretic mobility-shift assays demonstrated that Sp3 but not other Sp (specificity protein) family members binds to three of the Sp1 sites. Our present study suggests that Sp3 is involved in the basal transcriptional activation of the mStaf gene.
mStaf是一种锌指蛋白，可激活小鼠硒代半胱氨酸tRNA基因的转录。mStaf基因约35 kb长，分为16个外显子。所有外显子-内含子交界序列均符合GT/AG规则。转录起始位点位于起始密码子上游83 bp处。染色体定位将该基因定位于小鼠7号染色体E3-F1区域。近端启动子区域的序列分析揭示了几个潜在的调控元件；这些元件包括Sp1、Nkx、CP2、E2A、SIF（SIS诱导因子）、TFII-I和cAMP反应元件（CRE）的识别元件，但没有TATA序列。转染实验表明，mStaf基因的5'侧翼区域（-1894至+37）可驱动小鼠NMuMG细胞中的转录，并且包含-387至+37片段的构建体显示出最高的转录活性。缺失和突变实验表明，四个Sp1位点对基础启动子活性起重要作用。此外，电泳迁移率变动分析表明，Sp3而非其他Sp（特异性蛋白）家族成员与三个Sp1位点结合。我们目前的研究表明，Sp3参与了mStaf基因的基础转录激活。
