THE NUCLEOTIDE-SEQUENCE ENCODING THE HAMSTER 78-KDA GLUCOSE-REGULATED PROTEIN (GRP78) AND ITS CONSERVATION BETWEEN HAMSTER AND RAT

The complete nucleotide (nt) sequence encoding the hamster 78-kDa glucose-regulated protein has been determined using a cDNA plasmid p3C5. Comparison of the nucleotide sequences from rat and hamster showed a strong conservation in the coding region as well as 5''- and 3''-untranslated regions (UTRs). The relatively long (206 nt for rat) 5''UTR shares 72% sequence homology between rat and hamster in the 142 nt upstream from the ATG start codon. This conserved region contained an imperfect inverted-repeat sequence. The long 5'' UTR region is capable of forming stable dyad structures. The homology within the rat and hamster protein-coding region is 93.7%, with most of the differences resulting in silent site mutations. Out of the 654 amino acids, only four changes are detected, two of which are located in the signal peptide. While the sizes of the 3''UTR are different between the two species compared, strong sequence homologies (95%) were observed throughout the entire UTRs. Also, the 3''UTR was not rich in A + T residues as found in other eukaryotic mRNAs.