nested deletions with no blunt ends?

[Taunja Palmer-stone]

I need to do 3'nested deletions of an insert in a vector.  The only methods 
that I have come across for doing this involve the use of exonuclease III 
and end up generating blunt ends which are then ligated to recircularize 
the vector.  Does anyone know of any methods which do not generate blunt 
ends?  Thanks in advance.  Please reply by e-mail: 
tpalmer at gpu.srv.ualberta.ca.

Taunja