semi-quant pcr

[Clemens Suter-Crazzolara]

Hello,

a question about semi-quantitative PCR: I would like to have
a control primer pair of a gene that is constitutively expressed
in the eukaryotic (rat) cell. Up to now I have been using S12:
a very abundant ribosomal protein. Disadvantage; S12 is so abundant, 
that all cDNAs must be diluted 1000-fold before anything can be     
concluded.  
Do you know of a rather rare RNA that is constitutively expressed
in the cell ? Also, would it be theoretically possible to mix
the standard primers with the target primers in one reaction...
and still be semi-quantitative ? (somebody in our lab is trying
this, however I can imagine both primer pairs me interfere 
with eachother...)

clemens, Heidelberg