Siculella Luisa, Sabetta Simona, di Summa Roberta, Leo Monica, Giudetti Anna Maria, Palmieri Ferdinando, Gnoni Gabriele Vincenzo
Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Laboratorio di Biochimica, Università di Lecce, Via Prov. Lecce-Monteroni, Lecce, Italy.
Biochem Biophys Res Commun. 2002 Dec 6;299(3):418-23. doi: 10.1016/s0006-291x(02)02666-9.
Starvation has been associated with a reduced citrate carrier (CTP) activity in rat liver mitochondria. In the present study the molecular mechanism responsible for this reduction was investigated. Northern blot analysis performed with hepatic total RNA showed a decrease of about 40% in the CTP mRNA abundance in starved rats, when compared to fed animals. Nuclear run-on assay did not reveal any appreciable difference in the rate of CTP mRNA synthesis between the two groups of animals, while the apparent half-life of CTP mRNA in hepatocytes from fed and starved rats was 11 and 6h, respectively. Therefore, these results suggest that in starved rats the regulation of hepatic CTP expression occurs at posttranscriptional level. Moreover, the reduced CTP activity in starved animals gradually increased by refeeding. The carrier activity reached fed rat values 6-9h following refeeding. Interestingly, the accumulation of CTP mRNA raised in parallel with the transport activity.
饥饿与大鼠肝脏线粒体中柠檬酸载体（CTP）活性降低有关。在本研究中，对导致这种降低的分子机制进行了研究。用肝脏总RNA进行的Northern印迹分析表明，与喂食动物相比，饥饿大鼠中CTP mRNA丰度降低了约40%。核转录分析未显示两组动物之间CTP mRNA合成速率有任何明显差异，而喂食和饥饿大鼠肝细胞中CTP mRNA的表观半衰期分别为11小时和6小时。因此，这些结果表明，在饥饿大鼠中，肝脏CTP表达的调节发生在转录后水平。此外，饥饿动物中降低的CTP活性通过再喂食逐渐增加。再喂食6 - 9小时后，载体活性达到喂食大鼠的水平。有趣的是，CTP mRNA的积累与转运活性平行升高。
