Jonathan Howarth wrote " I am currently studying gene expression in
Arabidopsis roots, stems, leaves, flowers and siliques and am looking
for a constitutive probe for my northerns."
Jon, check out Huang et. al. PNAS 90:10066-10070, a cyclophilin gene was
used as a constitutively expressed gene and is pretty good. More careful
analysis was done on the tomato version I think Gasser et. al PNAS
hope this helps,
amief at candelab.berkeley.edu