Cloning and sequencing of the cDNA for an RNA-binding protein from the Mexican axolotl: binding affinity of the in vitro synthesized protein

A full length cDNA for an RNA-binding protein (axolotl REP) with consensus sequence (RNP-CS) from the Mexican axolotl, Ambystoma mexicanum, has been cloned from a subtraction library. In vitro translation with synthetic mRNA and subsequent hybrid-arrested translation with a specific antisense oligonucleotide confirms that the axolotl REP cDNA encodes an approx. 16 kDa polypeptide, Computer-assisted analyses revealed amino acid similarities of 58-60% to various RNA-binding proteins and a 90 amino acid region at the amino-terminal end constituting the putative RNA-binding domain (RNP-CS) with two highly conserved motifs, RNP2 and RNP1. Phylogenetic analysis suggests that the putative RNA-binding protein from axolotl is unique. A binding assay with radiolabeled axolotl REP showed that this RNA-binding protein bound strongly with poly(A) and to a lesser degree with poly(U), but not at all with poly(G), poly(C), or DNA. (C) 1998 Elsevier Science B.V. All rights reserved.