Messenger RNA (mRNA) expression levels may be calculated through various experimental methods. Through these experiments, the data obtained from them allow scientists to calculate the rates of synthesis and decay for mRNA within a cell. Unfortunately, due to the various experimental methods, the data obtained from them do not provide consistent data or show similar genetic patterns. Each method will classify the different mRNAs within the cell as stable or unstable, and this classification allows scientists to the determine sequence stability, as well as rate of decay. Also, these experiments will provide a ratio of newly developed messenger RNA to fully developed messenger RNA. This ratio allows scientists to calculate the rate of synthesis for mRNA. This combined data represents total turnover for mRNA expression within the cell.

           As mentioned, there are various methods that provide rates of synthesis and decay for messenger RNA. Some of the most used methods include, metabolic labeling, transcription inhibition with the use of drugs or mutation, and transcriptional control with the use of substitutional promoters. Transcription control and transcription inhibition allow gene expression to shut off and this will lead to a decrease in mRNA levels. During transcription inhibition, all genes will be shut off, while in transcriptional control, only a single gene will be shut off and examined. When comparing the data in each method, most data may have no correlation and no observable patterns. Since there have been no efforts to establish a more direct and efficient method to connect the patterns and results, scientist have developed a new method of determining messenger RNA expression levels.

           The newly developed method is called “multiplexed gene control” (MGC), and by shutting off gene expression within the cell, it allowed them to measure the rates of synthesis, and the half-lives for mRNA. During this experimentation, scientists performed this method on S. cerevisiae, a species of yeast. In the beginning, they modified promoters to shut off gene expression. In order to identify the experimental mRNA, they would mark each modified gene with a silent mutation. After experimentation, scientists obtained data that showed some unique patterns, and showed some correlation between other methods.

           This newly developed method showed a higher messenger RNA turnover value compared to the other methods. Scientists also noticed that this method provided faster and more consistent half-life measurements. The median half-life value obtained was 2.00 minutes. This value was 6 to 15 times shorter compared to other scientific methods. The unmodified, natural mRNAs had similar ratios compared to those that were marked with the modified promoters. This evidence shows that multiplexed gene control does not affect the half-life values and overall will provide reliable and consistent results in each experiment. Another unique pattern discovered through the MGC method, is the effect of mRNA half-lives on total gene networks. If messenger RNA were to affect the gene network, this would change the turnover rates for other molecules within the cell.

           The experiment and the data obtained allowed the scientists to connect patterns within the various methods. This method would also highlight the importance of other molecules within a cell and the gene network. Although this experiment involves yeast, this method could also be used on other biological organisms. Each organism will provide different results in rates of synthesis and degradation.

Work(s) Cited:

Baudrimont, A. et al. Multiplexed gene control reveals rapid mRNA turnover. Science Advances 3; https://www.science.org/doi/10.1126/sciadv.1700006 (2017).