Scientists have created a new tool that can help design proteins with specific functions, like turning genes on or off. Traditional methods for designing proteins don't work well for parts of the protein that don't fold into a specific shape, called intrinsically disordered regions. The researchers trained a computer model to generate sequences for these regions and then used another technique to control which features are included in the design. This allowed them to create proteins with more accurate predictions of where they would be found inside cells and how well they would regulate gene expression.