The invention relates to DNA-sequences, their use and the use of DNA-sequences of the MAG gene or genes encoding the high mobility group proteins, agents for the treatment of various diseases including tumors, influencing the development of the vascular system, as well as for contraception and tissue regeneration, and appropriate kits and processes. The sequences, agents, uses, kits and processes enable the specific influencing of molecular mechanisms that jointly form the basis for various diseases, the development of the vascular system, the contraception and the regeneration of tissue. Thus, the disadvantages associated with other agents or processes are decreased.