Imagine you discover a yeast mutant that exhibits a general inability to grow and thrive compared to wild-type yeast. You predic
t that the mutant has a defect in a basic process necessary for survival and therefore examine the cellular levels of 200 common proteins, as well as the levels of tRNAs and rRNAs. You discover that tRNA and rRNA levels are normal, but the levels of all of the proteins you examine are much lower than they are in the wild-type yeast. This suggests that there is a general defect in:
If the tRNA and rRNA levels are normal we can assume that the translation machinery is working properly. So, this suggest that the defect might appear in some of the previous steps of gene expression: replication, transcription, mRNA processing.
Gene expression is a set of processes that occur in the cell and that use information from the genetic material (gene) to produce gene product (e.g. protein). Gene expression is highly controlled and regulated because it is critical for an organism's development.
