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Study of the eIFG1-eIF1 interaction by TCP-seq on translation initiation in HEK 293T cells

ABSTRACT: Start codon recognition by the 48S complex is a critical step in translation. However, understanding the in vivo initiation and its regulation at a global scale is limited. Here, we analyzed translation complex profiling (TCP-seq) data to determine the impact of eIF4G1-eIF1 inhibition and the 48S organization. Our analysis provides the first global view of leaky scanning and reveal the central roles of mRNA features and eIF4G1-eIF1 in its regulation. Specifically, non-leaky genes are enriched with a Kozak bearing a C at -1 position while those with short 5’ UTR with TISU. Additionally, the stability of the 48S complex and its integrity during scanning are impaired upon eIF4G1-eIF1 inhibition. Detailed analysis of initiation site footprints revealed three main classes conserved from yeast to human. Our analysis provides a general overview of AUG selection and evidence for conformational rearrangements in vivo.

ORGANISM(S): Homo sapiens

PROVIDER: GSE226132 | GEO | 2024/03/27

REPOSITORIES: GEO

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Study of the translation initiation by Selective TCP-seq in the context of eIF1-eIF4G1 inhibitor

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2017-09-13 | PXD004980 | Pride

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Project description:Regulated start codon selection has the potential to reshape the proteome through the differential production of uORFs, canonical proteins, and alternative translational isoforms. However, conditions under which start codon selection is altered remain poorly defined. Here, using transcriptome-wide translation initiation site profiling, we reveal a global increase in the stringency of start codon selection during mammalian mitosis. Low-efficiency initiation sites are preferentially repressed in mitosis, resulting in pervasive changes in the translation of thousands of start sites and their corresponding protein products. This increased stringency of start codon selection during mitosis results from increased associations between the 40S ribosome and the key regulator of start codon selection, eIF1. We find that increased eIF1-40S ribosome interactions during mitosis are mediated by the release of a nuclear pool of eIF1 upon nuclear envelope breakdown. Selectively depleting the nuclear pool of eIF1 eliminates the changes to translational stringency during mitosis, resulting in the altered synthesis of thousands of protein isoforms. In addition, preventing mitotic translational rewiring results in substantially increased cell death and decreased mitotic slippage in cells that experience a mitotic delay induced by anti-mitotic chemotherapeutics. Thus, cells globally control translation initiation stringency with critical roles during the mammalian cell cycle to preserve mitotic cell physiology.

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