[en] Nuclei located on or close to the N=Z line have been generating a considerable interest during the last few years. This region gives us a unique opportunity to investigate some fundamental problems in nuclear physics like isospin symmetry of nuclear interaction. The isospin T is a good quantum number under the fundamental assumptions of charge symmetry and charge independence of the strong nuclear force. If isospin symmetry holds in nuclear interaction, then the level schemes and strength of E1 transitions between analog states of a mirror pair should be identical. Moreover, ΔT=0 E1 transitions are forbidden in N=Z self conjugate nuclei by isospin selection rules. Therefore, isospin symmetry breaking effects can be studied by investigating the level structures of mirror or self-conjugate nuclei