Ercikan-Abali E A, Banerjee D, Waltham M C, Skacel N, Scotto K W, Bertino J R
Program of Molecular Pharmacology and Therapeutics, Cornell University Medical College, Memorial Sloan-Kettering Cancer Center, New York 10021, USA.
Biochemistry. 1997 Oct 7;36(40):12317-22. doi: 10.1021/bi971026e.
Previous studies suggest that dihydrofolate reductase (DHFR) regulates its own translation. Moreover, intracellular levels of DHFR protein increase following exposure to the antifolate methotrexate (MTX), suggesting that MTX may release the translational inhibition mediated by DHFR [Chu et al. (1993) Biochemistry 32,4756-4760; Ercikan et al. (1993) Adv. Exp. Med. Biol. 338, 537-540]. To further investigate the role of DHFR in translational autoregulation, we have considered the possibility that DHFR directly contacts its cognate mRNA. Binding studies using a series of truncated DHFR mRNAs as probes localized the DHFR/RNA interaction to a 100-base-pair region containing two putative stem-loop structures; initial studies indicated that both of these loop structures are involved in protein binding. Moreover, the binding of MTX to DHFR prevents interaction of the protein with its cognate mRNA, thereby relieving translational autoregulation.
先前的研究表明，二氢叶酸还原酶（DHFR）调节其自身的翻译过程。此外，在暴露于抗叶酸药物甲氨蝶呤（MTX）后，细胞内DHFR蛋白水平会升高，这表明MTX可能解除了由DHFR介导的翻译抑制作用[Chu等人（1993年），《生物化学》32卷，4756 - 4760页；Ercikan等人（1993年），《实验医学与生物学进展》338卷，537 - 540页]。为了进一步研究DHFR在翻译自调控中的作用，我们考虑了DHFR直接与其同源mRNA接触的可能性。使用一系列截短的DHFR mRNA作为探针进行的结合研究，将DHFR与RNA的相互作用定位到一个包含两个假定茎环结构的100个碱基对区域；初步研究表明，这两个环结构都参与蛋白质结合。此外，MTX与DHFR的结合会阻止该蛋白与其同源mRNA的相互作用，从而解除翻译自调控。
