transcript lifetime ~20 - 30min: protein halflife 10 - 45min min
||Mouse Mus musculus
||Bahar Halpern K. et al., Bursty gene expression in the intact mammalian liver. Mol Cell. 2015 Apr 2 58(1):147-56. doi: 10.1016/j.molcel.2015.01.027. p.151 right column bottom paragraph to p.152 left column top paragraphPubMed ID25728770
||P.148 left column bottom paragraph:"To assess the intrinsic variability in the expression of liver genes, [investigators] imaged individual mRNA molecules in mouse liver frozen sections using smFISH [Single molecule fluorescence in situ hybridization](Itzkovitz et al., 2012 and Lyubimova et al., 2013) (Figures 1 and S1). [They] used simultaneous DAPI [4',6-diamidino-2-phenylindole, a fluorescent stain] nuclear staining and phalloidin membrane staining to assign mRNA dots to individual cells. [They] developed an in situ ploidy classification algorithm (Supplemental Experimental Procedures) that enabled stratifying [their] single-cell mRNA counts by both tissue zone and ploidy class (Figures S1D–S1F)."
||P.151 right column bottom paragraph to p.152 left column top paragraph:"[Investigators'] in situ measurements indicated that the gluconeogenic gene G6pc [Glucose-6-phosphatase, catalytic subunit (glucose 6-phosphatase alpha)] has a particularly short transcript lifetime of ∼20–30 min (Figures 4B and 5 Table S1). To assess the impact of this feature on protein content, [they] measured G6PC protein levels before and after 1 hr of refeeding. Strikingly, [they] observe not only an almost complete shutdown of transcription and a decline of ∼70% in mRNA concentrations, but also a decline of ∼60% in protein concentrations over this period (Figures 5C and 5D). This decline indicates that G6PC protein is also highly unstable under these conditions (protein half-life of 10–45 min, depending on whether translation rates change Supplemental Experimental Procedures). This half-life is particularly short, considering that median protein half-lives are on the order of 50 hr in mammalian cells (BNID 106377)."