TUMOR-NECROSIS-FACTOR-ALPHA REGULATION OF GLUCOSE-TRANSPORTER (GLUT1)MESSENGER-RNA TURNOVER - CONTRIBUTION OF THE 3'-UNTRANSLATED REGION OF THE GLUT1 MESSAGE

In the current study we report on the contribution of the GLUT1 3'-unt ranslated region (UTR) to the stability of the GLUT1 mRNA. To facilita te these investigations, a hybrid construct was prepared by insertion of the GLUT1 3'-UTR into a normally stable reporter gene coding for pr eproinsulin, The GLUT1 3'-UTR conferred lability to the otherwise long lived construct and transferred an ability to be stabilized in respon se to treatment with the cytokine, tumor necrosis factor-alpha (TNF), The destabilizing element has been mapped to a region located between bases 2242 and 2347 of the GLUT1 3'-UTR; this same region also mediate s the stabilization response to TNF, In vitro RNA protein binding assa ys using protein extracts from control and TNF-treated cells demonstra ted that two proteins, one of 37 kDa and the other of 40 kDa, recogniz ed sequence elements within the stability-determining region and were up-regulated in response to TNF treatment, The RNA-binding activity of these proteins coincides with the stabilization of the GLUT1 message, suggesting that they may be involved in regulation of the turnover of this message.