Molecular cloning and nucleotide sequences of cDNAs specific for rat liver ribosomal proteins S17 and L30

Abstract

cDNA clones coding for rat liver ribosomal proteins S17 and L30 have been isolated by positive hybridization-translation assay from a cDNA library prepared from 8-9S poly(A) + RNA from free polysomes of regenerating rat liver. The cDNA clone specific for S 17 protein (pRS 17-2) has a 466-bp insert with the poly(A) tail. The complete amino acid(aa) sequence of S 17 protein was deduced from the nucleotide sequence of the cDNA. S17 protein consists of 134 aa residues with an M r of 15377. The N-terminal aa sequence of S17 protein determined by automatic Edman degradation is consistent with the sequence data. The aa sequence of S17 shows strong homology (76.9%) to that of yeast ribosomal protein 51 [Teem and Rosbash, Proc. Natl. Acad. Sci. USA 80 (1983) 4403-4407] in the two-thirds N-terminal region. The cDNA clone specific for L30 protein (pRL30) has a 394-bp insert. The aa sequence of L30 protein was deduced from the nucleotide sequence of the cDNA. The protein consists of 114 aa residues with an M r of 12652. When compared with the N-terminal aa sequence of rat liver L30 protein [Wool, Annu. Rev. Biochem. 48 (1979) 719-754], pRL30 was found not to contain the initiation codon and 5'-noncoding region. The cDNA showed twelve silent changes in the coding region, one point mutation and one base deletion in the 3 ' -noncoding region, compared with mouse genomic DNA for L30 protein [Wiedemann and Perry, Mol. Cell Biol. 4 (1984) 2518-2528].