Ribozymes

[Bradley A. Arrick]

I am interested in the use of ribozymes expressed from eukaryotic
expression constructs, with the goal of suppressing the level of a
particular mRNA species following stable transfection of a mammalian
cell line. Are there good expression constructs out there?  Does the
ribozyme have to be excised to be functional, or can it remain as part
of a larger RNA species?  Hammerhead vs hairpin.
Thanks.