Hel-N1, an RNA-binding protein, is a ligand for an A + U rich region of the GLUT1 3' UTR.

Hel-N1, is an RRM protein which is a mammalian homologue of the Drosophila melanogaster RNA binding protein, ELAV (embryonic lethal abnormal vision). Hel-N1 binds to RNA containing short stretches of uridylates similar to those found in the 3' untranslated regions (3'-UTRs) of oncoprotein and cytokine mRNAs. The GLUT1 glucose transporter has an extensive 3' UTR that is AU-rich reminiscent of the 3'UTR of an oncogene mRNA. An in vitro RNA binding assay using Hel-N1 demonstrated binding to a specific portion of the GLUT1 3'UTR. Analysis of the folding pattern of this region depicted the retention of a stem loop structure, wherein the loop is composed of a stretch of uridylates. To further analyze the potential function of Hel-N1, stable transfectants were made in the 3T3-L1 cell line. The transfectants have been characterized, and the presence of the Hel-N1 DNA and protein verified. Data indicate Hel-N1 is a ligand for GLUT1 and its binding affects the stability and translatability of the GLUT1 message.