Sec. 4. The employees of the:
(1) public employees' retirement fund; and
(2) teachers' retirement fund;
become employees of the system on July 1, 2011, without change in compensation, seniority, or benefits. An employee of the public employees' retirement fund who is a member of the public employees' retirement fund before July 1, 2011, and becomes an employee of the system after June 30, 2011, remains a member of the public employees' retirement fund after June 30, 2011. An employee of the teachers' retirement fund who is a member of the teachers' retirement fund before July 1, 2011, and becomes an employee of the system after June 30, 2011, remains a member of the teachers' retirement fund after June 30, 2011. An employee who becomes an employee of the system after June 30, 2011, is a member of the public employees' retirement fund, unless the director expressly determines otherwise.