title: The sup-7(st5) X gene of Caenorhabditis elegans encodes a tRNATrpUAG amber suppressor.
abstract: In earlier studies, we identified in Caenorhabditis elegans two informational suppressors sup-5 III and sup-7 X and recently showed that these suppressors acted via an altered tRNA to suppress translational termination at amber (UAG) stop codons. We now show that the sup-7 (st5) suppressor is a tRNATrpUAG amber suppressor. These studies utilized a radiolabeled purified tRNA fraction to identify hybridizing genomic sequences in a phage genomic library. DNA sequence analysis of the hybridizing segment of one clone showed that the probe recognized a tRNATrpUGG sequence. The sup-7 gene was shown to be one of an 11 or 12 member tRNATrp family by Southern blot analysis, taking advantage of an Xba I restriction site induced in the anticodon sequence by the mutational event to suppressor. Sequence analysis of a recombinant lambda clone containing sup-7 gene proved that sup-7(st5) is a tRNATrpUAG. This conclusive proof of the nature of sup7(st5) will permit unambiguous interpretation in genetic applications, and the availability of the cloned sequences may allow the sup-7 gene to be used to select for the reintroduction of DNA into C. elegans.
mesh_terms: D000818:Animals; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D002107:Caenorhabditis / Q000235:genetics*; D004262:DNA Restriction Enzymes; D004274:DNA, Recombinant; D009154:Mutation; D009693:Nucleic Acid Hybridization; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics*; D013489:Suppression, Genetic
chemical_list: D004274:DNA, Recombinant; D012346:RNA, Transfer, Amino Acyl; D004262:DNA Restriction Enzymes