Blood-Vessel (image) Max-Planck-Gesellschaft Caption Cross-section of a blood vessel of a normal mouse (left) and a mouse without G12/G13 proteins (right). In the genetically modified mouse, the muscle cells of the vessel wall begin to grow excessively, thus obstructing the blood flow. Credit MPI for Heart and Lung Research Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.