Translational frameshifting: implications for the mechanism of translational frame maintenance.

摘要: The ribosome rapidly translates the information in nucleic sequence of mRNA into amino acid proteins. As with any biological process, translation is not completely accurate; it must compromise antagonistic demands increased speed and greater accuracy. Yet, reading-frame errors are especially infrequent, occurring at least 10 times less frequently than other errors. How do ribosomes maintain reading frame so faithfully? Geneticists have addressed this question by identifying suppressors that increase error frequency. Most familiar frameshift suppressor tRNAs, though include mutant forms rRNA, ribosomal proteins, or factors. Certain sequences can also program frameshifting normal ribosomes. models suppression programmed describe apparently quite different mechanisms. Contemporary work has questioned long-accepted model for a unified explanation been proposed both phenomena. Quadruplet Translocation Model proposes tRNAs cause recognizing an expanded codon. new data inconsistent some implying may be invalid all. A involves slippage caused weak, near-cognate codon.anticodon interaction. This strongly resembles mechanism +1 frameshifting. mean infrequent result from two successive errors: misreading tRNA, which causes subsequent shift frame. Ribosomes avoid phenotypically serious restricting innocuous sense.