SAE-RNA: A Sparse Autoencoder Model for Interpreting RNA Language Model Representations
Taehan Kim, Sangdae Nam
TL;DR
SAE-RNA addresses the interpretability gap in RNA language models by discovering sparse, interpretable concepts within RiNALMo embeddings using an overcomplete SAE trained on token-level representations. The method maps these sparse features to RNA structural elements (stems, hairpins) and ncRNA families, revealing layer-wise progression from diffuse to sparse, type-selective activations. Through bpRNA-90 and RNAcentral evaluations, the work demonstrates that learned concepts align with biologically meaningful motifs and functional groups, offering a bridge between pretrained embeddings and human biology. This approach enables hypothesis generation and potential feature-aware fine-tuning, providing a practical pathway to steer RNA LMs without full model retraining.
Abstract
Deep learning, particularly with the advancement of Large Language Models, has transformed biomolecular modeling, with protein advances (e.g., ESM) inspiring emerging RNA language models such as RiNALMo. Yet how and what these RNA Language Models internally encode about messenger RNA (mRNA) or non-coding RNA (ncRNA) families remains unclear. We present SAE- RNA, interpretability model that analyzes RiNALMo representations and maps them to known human-level biological features. Our work frames RNA interpretability as concept discovery in pretrained embeddings, without end-to-end retraining, and provides practical tools to probe what RNA LMs may encode about ncRNA families. The model can be extended to close comparisons between RNA groups, and supporting hypothesis generation about previously unrecognized relationships.
