The judge of any court of record, the sheriff or deputy of the sheriff must not practice law; the clerk of the circuit court or the deputy of the clerk must not practice in the county of which he or she is clerk or deputy; the register or his or her partner or the deputy of the register must not practice in the court of which he or she is register or deputy; the clerk of the judge of probate must not practice in the court of which his or her principal is the judge.