Poster Presentation Australasian RNA Biology and Biotechnology Association 2026 Conference

Convergent, program-specific cis-regulation shapes the multi-layer translational response of starved yeast (#150)

Orlane Rossini 1 , Shafi mahmud 2 , Alice Cleynen 1 , Nikolay Shirokikh 2
  1. The National Centre for Scientific Research (CNRS), Université de Montpellier, Montpellier, France
  2. Australian Centre for RNA Therapeutics in Cancer, School of Human Sciences, University of Western Australia, Perth, WA, Australia
When nutrients run out, cells reprogram gene expression within minutes. mRNA stability, poly(A) tail length, chemical modifications and translation each contribute, yet have almost always been studied one axis at a time, leaving unresolved whether they act in parallel, redundantly or convergently on individual transcripts.

We exploit a unique strength of long-read nanopore direct RNA sequencing: transcript abundance, degradation rate, poly(A) length and m5C/m6A/pseudouridine status are read simultaneously from the same single molecules, measurements that each normally need a dedicated protocol. Profiling light and heavy polysome fractions of fed and 10-minute glucose-starved yeast, we fused these layers with Stochastic Translation Efficiency (STE), an AI readout of absolute protein synthesis independent of mRNA level, in a joint model whose feature effects are allowed to be program-specific.

This resolves the transcriptome into five translational programs invisible to any single layer: translation machinery, ribosome biogenesis and amino-acid/catabolic metabolism induced, secretory glycosylation sharply repressed, and a near-neutral housekeeping bulk. The same feature can predict activation in one program and repression in another, and effects negligible transcriptome-wide become dominant once the right transcripts are isolated. The repressed glycosylation program is specified by a convergent stack of independent cis-signatures: weakest start-codon context, heaviest uORF load, most structured AUG, poorest codon optimality and depletion of stabilising poly(A)-binding-protein targets, a genome-wide uORF repression opposite to canonical GCN4 control. Modification remodelling concentrates in the translating pool, converging on Ty retrotransposon transcripts, while multi-hit transcripts reach the highest translation rates.

Transcripts are thus not merely regulated by isolated events but pre-encoded, in their sequence, for the translational fate that starvation enacts.