Protein binding regions of the mRNAs for the 55 kDa tumor necrosis factor receptor and the glucose transporter 1: sequence homology and competition for cellular proteins.

Gene expression is influenced by mechanisms regulating mRNA degradation. Knowledge on regulatory RNA elements involved and on proteins interacting with them is still limited. A 33 nucleotide (nt) region of the 55 kDa tumor necrosis factor receptor (TNFR-55) mRNA, previously reported by us to engage in such interaction with proteins from U-937 cells, exhibits homology to a 38 nt regulatory region of the glucose transporter GLUT-1 mRNA. Labeled RNA fragments comprising these two regions bind similar sets of proteins. Upon phorbol ester-induced differentiation into macrophage-like cells, protein binding to both fragments is changed similarly. Furthermore, both compete with each other for protein binding. This suggests that GLUT-1 and TNFR-55 RNA share a novel protein binding RNA motif involved in regulation of their half life.