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首页> 外文期刊>Molecular and Cellular Biology >Organization and expression of the cell cycle gene, ts11, that encodes asparagine synthetase.
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Organization and expression of the cell cycle gene, ts11, that encodes asparagine synthetase.

机译：编码天冬酰胺合成酶的细胞周期基因ts11的组织和表达。

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The human ts11 gene was isolated on the basis of its ability to complement the mutation of the BHK cell cycle ts11 mutant, which is blocked in G1 at the nonpermissive temperature. This gene has now been identified as the structural gene for asparagine synthetase (AS) on the bases of sequence homology and the ability of exogenous asparagine to bypass the ts11 block. The ts11 (AS) mRNA has a size of about 2 kilobases and is induced in mid-G1 phase in human, mouse, and hamster cell lines. We have studied the organization and regulation of expression of the ts11 gene. The human ts11 gene consists of 13 exons (the first two noncoding) interspersed in a region of about 21 kilobases of DNA. Transient expression assays using the bacterial chloramphenicol acetyltransferase reporter gene identified two separate promoters: one (ts11 P1) contained in a 280-base-pair region upstream of the first exon and the other (ts11 P2) contained in the first intron. ts11 P1 produced about sixfold more chloramphenicol acetyltransferase activity than did ts11 P2 and had features of the promoters of housekeeping genes: high G + C content, multiple transcription start sites, absence of a TATA box, and presence of putative Sp1 binding sites. ts11 P2 contained a TATA sequence and other elements characteristic of a promoter, but so far we have no evidence of its physiological utilization. The ts11 gene was overexpressed in ts11 cells exposed to the nonpermissive temperature. Addition of asparagine to the culture medium led to a drastic decrease in mRNA levels and prevented G1 induction in serum-stimulated cells, which indicated that expression of the AS gene is regulated by a mechanism of end product inhibition.
机译：人ts11基因是根据其补充BHK细胞周期ts11突变体突变的能力而分离的，该突变体在非允许温度下在G1中受阻。根据序列同源性和外源天冬酰胺绕过ts11区块的能力，现已将该基因鉴定为天冬酰胺合成酶（AS）的结构基因。 ts11（AS）mRNA的大小约为2千碱基，在人，小鼠和仓鼠细胞系的G1中期被诱导。我们已经研究了ts11基因表达的组织和调控。人类ts11基因由13个外显子（前两个非编码）组成，散布在大约21 kb的DNA区域中。使用细菌氯霉素乙酰基转移酶报告基因进行的瞬时表达测定确定了两个独立的启动子：一个（ts11 P1）包含在第一个外显子上游的280个碱基对区域中，另一个（ts11 P2）包含在第一个内含子中。 ts11 P1产生的氯霉素乙酰转移酶活性是ts11 P2的六倍，并且具有管家基因启动子的特征：高G + C含量，多个转录起始位点，没有TATA框和假定的Sp1结合位点。 ts11 P2包含TATA序列和启动子的其他特征，但到目前为止，我们尚无其生理利用的证据。 ts11基因在暴露于非容许温度的ts11细胞中过表达。向培养基中添加天冬酰胺会导致mRNA水平的急剧下降并阻止血清刺激细胞中的G1诱导，这表明AS基因的表达受终产物抑制机制的调节。

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