Myogenesis, or the formation of muscle tissue, is an extremely complicated process, is essential for the proper functioning of the body. Depending on the type of muscle, they play different important functions. In vertebrata skeletal (striated) muscles allow skeletal movement (locomotion) and maintaining posture. They are built of long, cylindrical cells (myofibres) with numerous nuclei. Each myofibre is composed of many alternately oriented fibrils, resulting in a conspicuous banding. These striated muscles contract quickly and fatigue rapidly. Their development and regeneration are controlled by many genetic factors and some of the most important ones are myogenic regulating factors (MRF), including MyoD (or Myod1), myogenin, Myf5 and MRF-4. These proteins regulate the activity of many genes involved in development and regeneration of muscle tissue. They act in a complementary manner and numerous studies show they are expressed to varying degrees. The synthesis of non-functional or abnormal MRFs may lead to serious consequences and even death due to abnormal development of muscle tissue. MRF-regulated inhibition of myoblasts in their growth cycle is a crucial step in muscle formation.