RiboUnmix: Learning Shared Translational Dynamics from Biased and Noisy Ribo-seq Measurements
Organizations: Doctoral School Computer Science University of Vienna
Abstract
Ribosome profiling (Ribo-seq) measures ribosome distributions along mRNAs, but observed occupancy profiles also contain experiment-specific distortions and stochastic variability. Consequently, models that accurately predict measured profiles may reproduce technical effects rather than recover the underlying biology. We ask whether jointly modeling datasets collected under different experimental conditions can reveal shared, sequence-dependent patterns of ribosome occupancy. We introduce RiboUnmix, a probabilistic multi-dataset framework in which each expected measured profile is represented as a shared sequence-dependent signal modulated by a dataset-specific multiplicative factor. A negative-binomial observation model captures variability across replicates. We evaluate RiboUnmix on a controlled synthetic benchmark combining programmed translation kinetics, ribosome traffic, stochastic count sampling, and sequence-dependent experimental distortions. Because the underlying kinetics and distortions are known, recovery of the shared profile and dataset-specific effects can be assessed separately. Both inferred components correlate strongly with their targets, demonstrating that RiboUnmix can disentangle shared kinetic patterns from experimental effects. Across four organism-specific real-data benchmarks, RiboUnmix outperforms sequence-to-profile baselines in predicting measured profiles. Models trained independently on subsets of 114 HEK-derived datasets recover concordant shared profiles for held-out transcripts, and experiments varying the number and composition of training datasets show that the learned representation remains stable. RiboUnmix thus converts variation across experiments into evidence for reproducible sequence-dependent patterns of ribosome occupancy, supporting biological hypothesis generation from diverse Ribo-seq datasets.
Figures & tables
| Model | C. elegans | E. coli | Human (HEK293T) | S. cerevisiae |
|---|---|---|---|---|
| iXnos | 0.271 0.016 | 0.350 0.028 | 0.472 0.014 | 0.444 0.019 |
| RiboExp | 0.253 0.018 | 0.374 0.024 | 0.418 0.013 | 0.456 0.020 |
| Riboformer | 0.257 0.021 | 0.466 0.032 | 0.465 0.017 | 0.435 0.016 |
| Seq2Ribo | 0.201 0.017 | 0.236 0.028 | 0.222 0.012 | 0.347 0.014 |
| RiboMIMO | 0.325 0.024 | 0.516 0.028 | 0.461 0.016 | 0.502 0.019 |
| RiboUnmix | 0.335 0.026 | 0.556 0.027 | 0.539 0.019 | 0.517 0.024 |
Appendix figures & tables28 assets
Supplementary material from the paper’s appendix.
Appendix
| Bias feature | Multiplier | P-sites | Transcripts |
|---|---|---|---|
| 3 ′ CC | 5.0–6.0 | 943,724 | 19,266 |
| 3 ′ GG | 4.0–4.4 | 577,402 | 19,240 |
| 3 ′ AA | 2.8–3.2 | 785,775 | 19,160 |
| 3 ′ UU | 5.8–6.2 | 646,563 | 19,068 |
| 5 ′ CC | 5.2–5.6 | 706,527 | 19,242 |
| 5 ′ GG | 4.2–4.6 | 738,405 | 19,252 |
| Reference | Mean pair PCC | Pooled PCC | Log- RMSE | Calibration slope | Affected sites within 10% |
|---|---|---|---|---|---|
| Equal | |||||
| Depth-ranked |
| Dataset name | GSE | Sample accession(s) | Replicates |
|---|---|---|---|
| akichika_2019 | GSE122071 | SAMN10359332 | 1 |
| andreev_2015_rep1 | GSE55195 | SAMN02646670 | 1 |
| andreev_2015_rep2 | GSE55195 | SAMN02646671 | 1 |
| apostolopoulos_2024_Cas13 | GSE232383 | SAMN35056827, SAMN35056828 | 2 |
| apostolopoulos_2024_dCas13 | GSE232383 | SAMN35056823, SAMN35056824 | 2 |
| barrington_2023 | GSE202900 | SAMN28209264, SAMN28209265, SAMN28209266 | 3 |
| Component | Implemented raw quantity | Direction | Median [ – ] |
|---|---|---|---|
| Periodicity | Fraction of CDS P-sites in frame 0 | Higher | 0.62 [0.56–0.72] |
| CDS enrichment | Fraction of assigned P-sites falling in the CDS | Higher | 0.94 [0.93–0.95] |
| Depth | Base-10 logarithm of the CDS P-site count plus one | Higher | 6.81 [6.25–7.23] |
| Transcript support | Number of transcripts with CDS TPM | Higher | 11,896 [11,487–12,213] |
| RPF-length center | Absolute deviation from 30 nt of the median sample-level mean RPF length (nt) | Lower | 1.78 [0.89–2.87] |
| RPF-length spread | Median sample-level RPF-length interquartile range (nt) | Lower | 1.5 [1.0–3.0] |
| Panel | Datasets | Study groups | Training transcripts |
| 1 | 29 | 20 | 13,261 |
| 2 | 29 | 21 | 13,613 |
| 3 | 28 | 22 | 13,595 |
| 4 | 28 | 22 | 13,340 |
| Reference weights | Mean PCC ↑ | Mean RMSE ↓ |
|---|---|---|
| Uniform | ||
| Better-scoring, | ||
| Worse-scoring, | ||
| Better-scoring, | ||
| Worse-scoring, | ||
| Better-scoring, |
| Dataset | Organism / system | Assembly / Annotation / CDS model | RPF lengths (nt) | Profiles |
|---|---|---|---|---|
| stein_2021 | C. elegans N2 | WBcel235; Ensembl 115, longest CDS/gene | 20–35 | 2 |
| zhang_2016 | E. coli K-12 MG1655 | ASM584v2; one CDS/locus tag | 20–40 | 1 |
| stein_2021_yeast | S. cerevisiae BY4741 | R64-1-1; longest-CDS model | 20–35 | 2 |
| iwasaki_2014 | Human HEK293T | GRCh38; GENCODE v46 MANE Select | 26–34 | 4 |
| Architecture / setting | C. elegans | E. coli | Human | S. cerevisiae | Checkpoint criterion |
|---|---|---|---|---|---|
| iXnos native | 3,710 (28) | 1,010 (24) | 2,296 (22) | 2,538 (27) | minimum validation MSE |
| matched–U | 10,412 (30) | 3,307 (30) | 11,989 (14) | 4,043 (29) | minimum validation MSE |
| matched–W | 10,412 (30) | 3,307 (16) | 11,989 (14) | 4,043 (29) | minimum validation MSE |
| RiboExp native | 407 (170) | 409 (43) | 413 (68) | 418 (76) | maximum validation Pearson |
| matched–U | 10,412 (7) | 3,307 (24) | 11,989 (25) | 4,043 (47) | maximum validation Pearson |
| matched–W | 10,412 (18) | 3,307 (21) | 11,989 (29) | 4,043 (48) | maximum validation Pearson |
| C. elegans | E. coli | |||||
|---|---|---|---|---|---|---|
| Architecture / setting | Pearson | Spearman | RMSE | Pearson | Spearman | RMSE |
| iXnos native | 0.286 0.020 | 0.242 0.020 | 1.944 0.271 | 0.372 0.030 | 0.367 0.027 | 3.844 0.698 |
| matched–U | 0.241 0.019 | 0.211 0.015 | 2.403 0.367 | 0.344 0.024 | 0.350 0.017 | 4.062 0.640 |
| matched–W | 0.271 0.016 | 0.237 0.014 | 2.048 0.301 | 0.350 0.028 | 0.353 0.022 | 3.882 0.617 |
| RiboExp native | 0.269 0.022 | 0.239 0.017 | 2.219 0.371 | 0.364 0.026 | 0.359 0.021 | 5.176 1.401 |
| matched–U | 0.204 0.013 | 0.165 0.012 | 2.364 0.347 | 0.340 0.024 | 0.323 0.022 | 3.927 0.588 |