THE CARBOXYL EXTENSIONS OF 2 RAT UBIQUITIN FUSION PROTEINS ARE RIBOSOMAL-PROTEINS S27A AND L40

Two rat recombinant cDNAs were characterized; they encode fusion prote ins that have at their NH2 terminus the conserved 76 amino acid ubiqui tin and at their carboxyl terminus the extension ribosomal proteins S2 7a (SO amino acids and a molecular weight of 9,397) or L40 (52 amino a cids and a molecular weight of 6,177). The fusion proteins are process ed in a reticulocyte lysate to ubiquitin and either S27a or L40. Hybri dization of cDNAs to digests of nuclear DNA suggests that there are 14 to 19 copies of the S27a, and 6 to 10 of the L40, genes. The mRNA for ubiquitin-S27a has about 700 nucleotides and ubiquitin-L40 about 650. Ribosomal proteins S27a and L40 contain zinc finger motifs of the C-2 -C-2 variety. S27a and L40 are related to ribosomal proteins from othe r species. (C) 1995 Academic Press, Inc.