To the linux kernel, wine is just like any other program (X, kpaint, doom3, you name it), and anything running inside wine is just as native as a true linux application. Wine operates *completely* in user-land, as others have pointed above. It doesn't do a single instruction in kernel land, just like any other linux application.
For it to work inside the kernel there would need to be a wine.ko module or something similar, just like qemu has kqemu or virtualbox has also some modules. There's no need though, all wine does is to convert api calls from windows applications to linux native calls to the relevant component (linux itself, X, or whatever belongs on each case).
The regedit shipped within wine is not the windows regedit program. It's a clone created entirely using linux+the winelib foundations, and it's a true native linux application that just modifies the equivalent of the windows registry files, which lives in $HOME/.wine/, this registry is not a complete windows registry, wine doesn't need one to start with. It just includes some basic foundations so windows programs can find the minimum info they expect to run, plus of course the info that each program installs there when you install it using wine.
Your question doesn't make much sense so if this doesn't answer it, please, be more concrete and try to work the things better.