Involved in the control of the cell cycle at the G2/M (mitosis) transition. Expressed in the dividing region of the root cap and root apex. Expressed in the intercalary meristem of internodes and in adventitious roots under submergence conditions. Expressed in the G2/M phases and disappears at the metaphase of mitosis. By gibberellin (GA3) and submergence. Belongs to the cyclin family. Cyclin AB subfamily.