I am just looking for a number whether that is a mean or an estimate. I am having trouble finding this value on papers because the papers mention only the methods for calculating such a value. Is there a reason why a reasonable mean is hard to obtain?
Here is my best attempt at answering this question:
The median mRNA degradation lifetime is roughly 20 minutes in the case of yeast. Also, the total transcription for RNA pol II in a yeast cell growing in standard conditions is about 60200 mRNAs/h. I am going to go ahead and suppose that the transcription rate is constant throughout time. Thus we have that total transcription rate is equal to 1003 mRNAs/min. Furthermore, I am going to make the rough approximation that all mRNAs live exactly 20 minutes. Therefore, mRNAs will start degrading after 20 minutes. In one hour, 1003 mRNAs will degrade every minute for 40 minutes. It follows that the rate of mRNA decay in yeast is roughly 40120 mRNAs/h.