THE ELAV-LIKE PROTEINS BIND TO A CONSERVED REGULATORY ELEMENT IN THE 3'-UNTRANSLATED REGION OF GAP-43 MESSENGER-RNA

Previous studies have identified three brain proteins (40, 65 and 95 k Da, respectively) that specifically bind to the 5'-untranslated region of GAP-43 mRNA. In this study, using a specific monoclonal antibody, we now show that the 40-kDa proteins are members of the Elav-like prot ein family. This family of specific RNA-binding proteins comprise thre e neural specific members called HuD, HuC, and Hel-N1. We have shown t hat purified recombinant HuD can bind with high affinity to GAP 43 mRN A. In addition, we have mapped the binding site to a highly conserved 26-nucleotide sequence within the regulatory element, The binding of H uD to this site is readily displaced by RNA oligonucleotides encoding other HuD binding sites, We also show that only the first and second R NA binding domains of HuD are required for selective binding to GAP 43 mRNA.