Detailed histological assessment revealed that MKL1-Tg mice experienced more damaging colitis, especially of the proximal colon, as evidenced by the massive infiltration and penetration of inflammatory cells into the colonic tissues, including the lamina propria, submucosa, and muscle layers, and the destruction of the epithelial structure, accompanied by ulceration (Fig. 5D). The gene discussed is MRTFA; the disease is colitis.