Molecular cloning and nucleotide sequence of cDNA specific for rat ribosomal protein L5.

cDNA clones specific for rat ribosomal protein L5, which is the protein moiety of 5S RNA protein particles, were isolated by using a mixture of tetradecamer deoxyribonucleotide probes reflecting the amino acid sequence of the N-terminal portion of L5. A cDNA clone (pRL5-1) lacking the 3'-terminal region of L5 was isolated by hybrid-selected translation and shown to be L5-specific by the identity of the deduced amino acid sequence and that of the N-terminus of protein L5. pRL5-1 was then used to select another clone (pRL5-2) by colony hybridization which contained the entire coding region, 3'-non-coding region and poly(A) addition signal. The nucleotide sequence of L5-specific cDNA was determined by using these two clones. It contained a total of 1069 base pairs: 123 base pairs in the 5'-non-coding region, 894 base pairs in the coding region and 52 base pairs in the 3'-non-coding region. The poly(A) addition signal appeared at the 33rd nucleotide after the termination codon. The amino acid sequence deduced from this nucleotide sequence consists of 296 amino acids. The homology of amino acid sequence between L5 and other 5S RNA-binding proteins is discussed.