Feedback regulation of ornithine decarboxylase expression

FEBS Letters

Autelli, Riccardo²  Heby, Olle¹  Persson, Lo²  Holm, Ingvar¹ 

[1]Department of Zoophysiology, University of Umeå, S-901 87 Umeå, Sweden

[2]Department of Physiology, University of Lund, S-223 62 Lund, Sweden

关键词: Ornithine decarboxylase;    Polyamine;    Translational regulation;   

DOI  :  10.1016/0014-5793(90)80060-V

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The rate-controlling enzyme in polyamine synthesis, ornithine decarboxylase (ODC), is subject to feedback regulation by the polyamines at the level of translation. In the present study we used a cell-free translation system to further investigate the mechanism by which this regulation occurs. Lysates of ODC-overproducing cells were capable of synthesizing large amounts of ODC. The degree of initiation was poor in the lysates and the synthesis of ODC was mainly a result of continued elongation of peptide chains on pre-initiated ribosomes. By determining the amount of ODC produced in the lysate, we obtained an estimate of the number of ribosomes that were actively translating ODC mRNA at the moment of lysis. Using this polysomal run-off assay we demonstrated that the polyamine-mediated regulation of ODC synthesis occurs without any change in the number of ribosomes associated with the message. This finding indicates that the polyamines exert a coordinate effect on initiation and elongation.

【 授权许可】

Unknown