Transcript-wide m6A methylation defines the efficiency of cap-independent translation initiation.

N⁶-methyladenosine (m⁶A) plays an important role in translation control and, particularly, in cap-independent initiation. The impact of m⁶A is usually studied in the context of its location in the transcripts, but the global impact of m⁶A along mRNAs remains unclear. Here, we combined ribosome profiling under conditions of mTOR inhibition and m⁶A mapping to identify distinct subsets of mRNAs that differ in their sensitivity to the suppression of cap-dependent initiation. We found that the sensitivity strongly correlated with the total m⁶A methylation of the transcripts. Further, upon decreased mTOR activity, m⁶A methylation facilitated the enhanced association of mRNAs with components of the eIF4F complex. Thus, the efficiency of cap-independent translation initiation is primarily defined not by precise localization but by the total level of m⁶A methylation, and m⁶A has a compensatory role in maintaining translation when the canonical cap-dependent pathway is impaired. Our findings underscore the significance of contemplating global m⁶A methylation status as a pivotal element in translational control, particularly under stress or signaling perturbations.