In the characterization of the range of the Radon transform, one encounters the problem of the holomorphic extension of functions defined on $\R^2\setminus\Delta_\R$ (where $\Delta_\R$ is the diagonal in $\R^2$) and which extend as ``separately holomorphic" functions of their two arguments. In particular, these functions extend in fact to $\C^2\setminus \Delta_\C$ where $\Delta_\C$ is the complexification of $\Delta_\R$. We take this theorem from the integral geometry and put it in the more natural context of the CR geometry where it accepts an easier proof and a more general statement. In this new setting it becomes a variant of the celebrated ``edge of the wedge" theorem of Ajrapetyan and Henkin.

We give a new proof of former results by G. Zampieri and the author on extension of holomorphic functions from one side $\Omega$ of a real hypersurface $M$ of $\mathbb{C}^n$ in the presence of an analytic disc tangent to $M$, attached to $\bar\Omega$ but not to $M$. Our method enables us to weaken the regularity assumptions both for the hypersurface and the disc.