Two molecular control factors play a decisive role in what is known as splicing, the cutting and assembly of mature messenger RNA – a prerequisite for protein synthesis in the cell. The poorly characterized factors are crucial to ensuring that the molecular machine responsible for splicing is working correctly. A research team led by Prof. Dr Ed Hurt at the Heidelberg University Biochemistry Center has deciphered how the two cellular quality inspectors work. The team collaborated with researchers from Fudan University in Shanghai (China).