Buffering exogenous perturbation is crucial to maintain transcriptional homeostasis during development.While mi RNAs have been speculated to play a role in stability maintenance, previous studies seeking to check this...Buffering exogenous perturbation is crucial to maintain transcriptional homeostasis during development.While mi RNAs have been speculated to play a role in stability maintenance, previous studies seeking to check this conjecture focused on measurements of transcript levels at steady state or involved individual mi RNA targets. We measured whole-genome expression dynamics by introducing a transient perturbation and establishing a perturbation and recovery system in Drosophila larvae. We inhibited all transcription and assayed transcriptomes at several time points during recovery from inhibition. We performed these experiments in the wild type and mi RNA-deficient genetic backgrounds. Consistent with theories about mi RNAs’ function in stabilizing the transcriptome, we find that attenuating mi RNA expression leads to weak impairment in degradation of targets but strong destabilization of target genes when transcription is re-activated. We further fitted a model that captures the essential aspects of transcription dynamics in our experiments and found that the mi RNA target transcripts uniformly overshoot the original steady state as they recover from a general inhibition of transcription if global mi RNA levels are reduced. Collectively, our results provide experimental evidence for the idea that mi RNAs act cumulatively to stabilize the transcriptional regulatory network. We therefore found a promising approach to assess the effect of these molecules on transcription dynamics.展开更多
基金supported by the National Natural Science Foundation of China (31801094 to C.L. and 31771416 to X.L.)the Key Research Program of the Chinese Academy of Sciences (KFZD-SW-220-1 to X.L.)+3 种基金CAS “Light of West China” Program (to X.L.)the National Natural Science Foundation of China (31900417 to G.L.)the National Key Basic Research Program of China (2014CB542006 to C.L.)China Postdoctoral Science Foundation (2019M653162 to G.L.)。
文摘Buffering exogenous perturbation is crucial to maintain transcriptional homeostasis during development.While mi RNAs have been speculated to play a role in stability maintenance, previous studies seeking to check this conjecture focused on measurements of transcript levels at steady state or involved individual mi RNA targets. We measured whole-genome expression dynamics by introducing a transient perturbation and establishing a perturbation and recovery system in Drosophila larvae. We inhibited all transcription and assayed transcriptomes at several time points during recovery from inhibition. We performed these experiments in the wild type and mi RNA-deficient genetic backgrounds. Consistent with theories about mi RNAs’ function in stabilizing the transcriptome, we find that attenuating mi RNA expression leads to weak impairment in degradation of targets but strong destabilization of target genes when transcription is re-activated. We further fitted a model that captures the essential aspects of transcription dynamics in our experiments and found that the mi RNA target transcripts uniformly overshoot the original steady state as they recover from a general inhibition of transcription if global mi RNA levels are reduced. Collectively, our results provide experimental evidence for the idea that mi RNAs act cumulatively to stabilize the transcriptional regulatory network. We therefore found a promising approach to assess the effect of these molecules on transcription dynamics.
