Your DNA has a secret “second code” that decides which genes get silenced

April 9, 2026 Source: Kyoto University Not all parts of our genetic code are equal, even when they appear to say the same thing. Scientists have discovered that cells can detect less efficient genetic instructions and selectively silence them. A protein called DHX29 plays a key role in this process by identifying and suppressing weaker messages. This finding reveals a hidden layer of control in how genes are used. To investigate this question, a research team from Kyoto University and RIKEN, led by Osamu Takeuchi and Takuhiro Ito, carried out a series of experiments aimed at uncovering how cells handle codon efficiency. They began with a genome-wide CRISPR screening to identify factors involved in codon-dependent gene expression. This approach pointed to an RNA-binding protein called DHX29 as a key player. Follow-up RNA sequencing allowed the researchers to examine overall mRNA activity, revealing that when DHX29 is missing, mRNAs containing non-optimal codons increase in abundance. >> How DHX29 Detects and Suppresses Weak Genetic Messages Using cryo-electron microscopy, the team was able to observe how DHX29 physically interacts with the 80S ribosome, the cellular machinery responsible for protein production. Additional analysis using selective ribosome profiling showed that DHX29 is more likely to associate with ribosomes that are reading non-optimal codons. Further proteomic studies revealed that DHX29 recruits the GIGYF2•4EHP protein complex. This complex acts to selectively suppress mRNAs that contain non-optimal codons, effectively reducing the production of inefficient genetic messages. These findings change how scientists think about gene regulation, showing that codon choice itself plays a direct role in controlling gene expression in human cells. The DHX29-driven mechanism could influence important biological processes such as cell differentiation, maintaining cellular balance, and the development of cancer, suggesting wide-ranging significance.