Ribozyme that cleaves at 3' end or.....?

[Peter Russell]

I want to express in yeast from a nuclear plasmid the following:

sequence that self-cleaves at 3' end----RNA sequence of
interest---sequence that self-cleaves at 5' end.

In other words I am trying to make an RNA with defined 5' and 3' ends
(it is a viral RNA so the ends are important for replication
competence). The 3' end I can handle with the HDV antigenomic ribozyme,
but what can be used to give the "perfect" 5' end?  [BTW I have tried
the T7  promoter and T7 RNA polymerease expressed from a nuclear plasmid
and that has not worked properly.]

TIA for your help.

Peter Russell
Reed College
yeast at reed.edu