  Based on an effective nucleon-nucleon interaction, a microscopic cluster
model of the nucleus-nucleus bremsstrahlung, including implicitly a part of the
effects of meson-exchange currents via an extension of the Siegert theorem is
applied to the $\alpha+p$ and $\alpha+n$ systems. The contributions of the $E1$
and $E2$ transitions to the bremsstrahlung cross sections are evaluated and
their relative importance for the mirror systems $\alpha+p$ and $\alpha+n$ is
compared. Another approach based on realistic two- and three-nucleon
interactions and the No-Core Shell Model/Resonating-Group Method is also
investigated. Some preliminary results for the $\alpha+p$ bremsstrahlung are
displayed.
