THE LEADER PEPTIDES OF ATTENUATION-REGULATED CHLORAMPHENICOL RESISTANCE GENES INHIBIT TRANSLATIONAL TERMINATION

Placing a translation stop codon at the ribosomal pause site in the le ader of the attenuation-regulated cat-86 gene activates cat expression in the absence of the inducer, chloramphenicol. Genetic experiments h ave shown that this phenomenon depends on the amino acid sequence of t he leader-encoded peptide and could readily be explained if the peptid e was an inhibitor of translation termination. Here we demonstrate tha t the cat-86 leader pentapeptide is an in vitro inhibitor of translati on termination in addition to its previously described antipeptidyltra nsferase activity.