Project description:Two-color microarray experiment compariing the profiles of CBP80-associated mRNAs and eIF4E-associated mRNAs in actively translating polysomes.
Project description:eIF4E, the major cap-binding protein, has long been considered limiting for translating the mammalian genome. However, the requirement for eIF4E dose at an organismal level remains unexplored. By generating an Eif4e haploinsufficient mouse, we surprisingly found that 50% reduction in eIF4E, while compatible with normal development and global protein synthesis, significantly impeded cellular transformation and tumorigenesis. Genome-wide translational profiling uncovered a translational program induced by oncogenic transformation and revealed a critical role for eIF4E dose specifically in translating a network of mRNAs enriched for a unique 5’UTR signature. In particular, we demonstrate that eIF4E dose is essential for translating mRNAs regulating reactive oxygen species (ROS) that fuel transformation and cancer cell survival in vivo. Therefore, mammalian cells have evolved surplus eIF4E levels that cancer cells hijack to drive a translational program supporting tumorigenesis Total cellular RNA and high MW polysome associated RNA were isolated from matched untransformed and transformed WT and Eif4e+/- MEFs for analysis on Affymetrix Mouse Gene 1.0 ST arrays. The difference in log2 RMA intensity between matched polysomal RNA and total RNA was taken to quantify translational efficiency (TE).
Project description:eIF4E, the major cap-binding protein, has long been considered limiting for translating the mammalian genome. However, the requirement for eIF4E dose at an organismal level remains unexplored. By generating an Eif4e haploinsufficient mouse, we surprisingly found that 50% reduction in eIF4E, while compatible with normal development and global protein synthesis, significantly impeded cellular transformation and tumorigenesis. Genome-wide translational profiling uncovered a translational program induced by oncogenic transformation and revealed a critical role for eIF4E dose specifically in translating a network of mRNAs enriched for a unique 5’UTR signature. In particular, we demonstrate that eIF4E dose is essential for translating mRNAs regulating reactive oxygen species (ROS) that fuel transformation and cancer cell survival in vivo. Therefore, mammalian cells have evolved surplus eIF4E levels that cancer cells hijack to drive a translational program supporting tumorigenesis
Project description:Deciphering the regulatory network for human naïve and primed pluripotency is of fundamental theoretical and applicable significance. Here, by combining quantitative proteomics, phosphoproteomics and acetylproteomics analyses, we revealed RNA processing and translation as the most differentially-regulated processes between naïve and primed human embryonic stem cells (hESCs). While glycolytic primed hESCs rely predominantly on eIF4E-mediated cap-dependent pathway for protein translation, naïve hESCs with reduced mTORC1 activity are more tolerant to blockage of eIF4E-dependent translation, and their bivalent metabolism allows for translating selective mRNAs via both eIF4E-dependent and eIF4E-independent/eIF4A2-dependent pathways to form a more compact naïve proteome. Globally up-regulated proteostasis system and down-regulated post-translational modification system help to further refine and maintain the naïve proteome that is compatible with the more rapid cycling of naïve hESCs, where CDK1 plays an indispensable coordinative role.
