One of the fascinating aspects of highly ionized atoms is that their study may provide new sensitive tests of quantum electrodynamics in strong external fields. For the analysis of proposed high-precision e~~erimentsl-~ with one-, two-, or three-electron uranium 9:8~ a precise knowledge of the electronic spectrum is required. The influence of the finite nuclear size as well as quantum electrodynamical (QED) radiative corrections such as vacuum polarization and self-energy effects on the binding energy of atomic states is well kno~n.~-l' At very high precision the additional energy shift of K-shell electrons due to nuclear polarization may become relevant. The interaction with internal nuclear degrees of freedom has been extensively studied in the context of muonic atom~,'~-'~ where the resulting energy corrections can be relatively large since binding energies of muons are of the Same order as typical nuclear excitation energies. Analogous calculations performed in the case of electronic at~ms'~~'~ showed that the predicted energy shifts are much smaller. However, the influence of this contribution increases when the interaction with lowlying nuclear rotational modes is taken into account. One reason is that for heavy elements such as uranium the electronic transition energies become comparable in magnitude with nuclear excitation energies. Our treatment of the energy shift of strongly bound electrons is based on the introduction of an effective photon propagator containing nuclear-polarization insertions. The effect of nuclear polarization thus appears as part of the radiative corrections to the electron energy. We are particularly concerned with the energy shift of the lsl,, state for a ;:'U nucleus, which is the focus of various planed experiments, because it has the highest practically accessible nuclear charge. Let us first give a brief description of our formal framework. The nuclear charge is described by the electromagnetic current