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

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.