Abstract
Studies on regulation of gene expression have contributed substantially to understanding mechanisms for the long-term activity-dependent alterations in neural connectivity that are thought to mediate learning and memory. Most of these studies, however, have focused on the regulation of mRNA transcription. Here, we utilized high-throughput sequencing coupled with ribosome footprinting to globally characterize the regulation of translation in primary mixed neuronal-glial cultures in response to sustained depolarization. We identified substantial and complex regulation of translation, with many transcripts demonstrating changes in ribosomal occupancy independent of transcriptional changes. We also examined sequence-based mechanisms that might regulate changes in translation in response to depolarization. We found that these are partially mediated by features in the mRNA sequence—notably upstream open reading frames and secondary structure in the 5′ untranslated region—both of which predict downregulation in response to depolarization. Translationally regulated transcripts are also more likely to be targets of FMRP and include genes implicated in autism in humans. Our findings support the idea that control of mRNA translation plays an important role in response to neural activity across the genome.
Highlights
Stimulated neurons show an activity-mediated gene expression program that results in the remodeling of brain circuitry (Goelet et al, 1986; Sheng and Greenberg, 1990)
We found that: (i) an even higher proportion of genes are altered translationally than is evident from transcription alone, (ii) overall translation is reduced in response to sustained neuronal stimulation, (iii) as many as 40% of mRNAs showing a change in translation do so independently of changes in mRNA levels, (iv) models taking into account 5′untranslated region (UTR) secondary structure and upstream open reading frames (uORFs) together can explain a portion of this regulation, and (v) downregulated transcripts are significantly enriched in targets of the RNAbinding proteins (RBP) Fragile X Mental Retardation Protein (FMRP)
We performed genome wide nucleotide-level analysis of transcription and translation to quantify the extent of translational regulation in response to sustained KCl stimulation
Summary
Stimulated neurons show an activity-mediated gene expression program that results in the remodeling of brain circuitry (Goelet et al, 1986; Sheng and Greenberg, 1990). Because this program contributes to essential functions such as learning and memory, extensive transcriptomic studies in vitro and in vivo have defined the genes transcribed in response to neuronal activity as well as molecular mechanisms regulating such activity-dependent transcription (Ghosh and Greenberg, 1995; Kim et al, 2010; West and Greenberg, 2011; Malik et al, 2014). The relative magnitude of transcriptional vs. translational regulation for gene expression has not yet been defined
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have