西亚试剂： Requires the Cooperation of Tristetraprolin and RCK/P54.

AU-Rich Element-Dependent Translation Repression Requires the Cooperation of Tristetraprolin and RCK/P54.

Mei-Yan Qi1, Zhi-Zhang Wang1, Zhuo Zhang2, Qin Shao1, An Zeng1, Xiang-Qi Li1, Wen-Qing Li1, Chen Wang1, Fu-Ju Tian1, Qing Li1, Jun Zou1, Yong-Wen Qin2, Gary Brewer1,4, Shuang Huang2,3 and Qing Jing1,2,*

AU-rich elements (AREs), residing in the 3′ UTR of many labile mRNAs, are important cis-acting elements to modulate the stability of these mRNAs by collaborating with trans-acting factors such as Tristetraprolin (TTP). AREs also regulate translation, but the underlying mechanism is not fully understood. Here we examined the function and mechanism of TTP in ARE-mRNA translation. Through a luciferase-based reporter system, we demonstrate that TTP represses ARE reporter mRNA translation by employing knockdown, overexpression, and tethering assays in 293T cells. Polyribosome fractionation experiments showed that TTP shifts target mRNAs to lighter fractions. In murine RAW264.7 macrophages, knocking down TTP produces significantly more TNF-α than the control, while the corresponding mRNA level has a marginal change. Furthermore, knockdown of TTP increases the biosynthesis rate of TNF-α cytokine, suggesting that TTP can exert effects at translational levels. Finally, we demonstrate that general translational repressor RCK may cooperate with TTP to regulate ARE-mRNA translation. Collectively, our studies reveal a novel function of TTP in repressing ARE-mRNA translation and that RCK is a functional partner of TTP in promoting TTP-mediated translational repression.