天冬酰胺基-tRNA在一种哺乳动物细胞系中天冬酰胺合成酶调节中的作用。
A role for asparaginyl-tRNA in the regulation of asparagine synthetase in a mammalian cell line.
作者信息
Arfin S M, Simpson D R, Chiang C S, Andrulis I L, Hatfield G W
出版信息
Proc Natl Acad Sci U S A. 1977 Jun;74(6):2367-9. doi: 10.1073/pnas.74.6.2367.
The expression of asparagine synthetase activity [L-aspartate:ammonia ligase (AMP-forming), EC 6.3.1.1] in cultured Chinese hamster ovary (CHO) cells is regulated by asparagine. After transfer of CHO cells from an asparagine-supplemented medium to a medium lacking asparagine, activity increases 1.5- to 2-fold. If asparagine is added back to the medium, activity returns to control levels. To test the possible involvement of Asn-tRNAAsn in regulating the levels of asparagine synthetase, we have examined the levels of asparagine synthetase in a mutant of CHO cells containing a temperature-sensitive asparaginyl-tRNA synthetase [L-asparagine:tRNA ligase (AMP-forming), EC 6.1.1.22]. Under conditions of limited asparaginyl-tRNA synthetase activity in the mutant, there is a 2- to 3-fold increase in the level of asparagine synthetase activity. Under identical conditions, there is no change in asparagine synthetase activity in the wild type. This correlation between asparaginyl-tRNA synthetase activity and asparagine synthetase levels may be a consequence of a direct role of tRNAAsn in the regulation of the in vivo expression of the asparagine synthetase structural gene.
培养的中国仓鼠卵巢（CHO）细胞中天冬酰胺合成酶活性[L-天冬氨酸：氨连接酶（生成AMP），EC 6.3.1.1]的表达受天冬酰胺调节。将CHO细胞从添加了天冬酰胺的培养基转移到缺乏天冬酰胺的培养基后，活性增加1.5至2倍。如果将天冬酰胺重新添加到培养基中，活性会恢复到对照水平。为了测试天冬酰胺-tRNAAsn可能参与调节天冬酰胺合成酶水平，我们检测了含有温度敏感型天冬酰胺-tRNA合成酶[L-天冬酰胺：tRNA连接酶（生成AMP），EC 6.1.1.22]的CHO细胞突变体中的天冬酰胺合成酶水平。在突变体中天冬酰胺-tRNA合成酶活性受限的条件下，天冬酰胺合成酶活性水平增加2至3倍。在相同条件下，野生型中的天冬酰胺合成酶活性没有变化。天冬酰胺-tRNA合成酶活性与天冬酰胺合成酶水平之间的这种相关性可能是tRNAAsn在体内调节天冬酰胺合成酶结构基因表达中直接作用的结果。
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