Studies on the translation of genetic message: role of ribosomal protein S12 in cistron selection.

Each cistron on an mRNA molecule has a certain probability of being selected for translation by a given species of ribosome. This cistron specificity, or uniqueness, results from several determinants in the protein synthesizing system, each independently contributing to the potential of that cistron as an efficient initiator. This thesis includes a review of the research done in recent years to demonstrate the factors which influence the efficiency of initiation on a given cistron. Following this, the role of one of these factors, ribosomal protein S12, is studied in detail. Most known RNA bacteriophages code for three proteins. These are the coat, which is the major structural protein of the virus particle, the A protein which is required for proper assembly of the virus, and synthetase, which combines with several of the host coded peptides to form an enzyme required for transcription of the phage. These viral messages are often used to study protein synthesis because they are small, and their protein products can be easily separated and compared. This research project is designed to study the in vitro protein synthesizing system of an E. coli streptomycin resistant mutant. Plaque formation by an RNA phage indicates that it can infect the parent but not the mutant