THE PLANT CELL, Vol 4, Issue 12 1471-1484, Copyright © 1992 by American Society of Plant Biologists
Cauliflower Mosaic Virus Gene VI Controls Translation from Dicistronic Expression Units in Transgenic Arabidopsis Plants
C. Zijlstra and T. Hohn
Friedrich Miescher-Institut, P.O. Box 2543, CH-4002 Basel, Switzerland
Transformed Arabidopsis plants were used to study the effect of the
cauliflower mosaic virus (CaMV) inclusion body protein on translation of
dicistronic RNA. Reporter plants contain a dicistronic transcription unit
with CaMV open reading frame VII (ORF VII) as the first and the
[beta]-glucuronidase (GUS) reporter ORF as the second cistron.
"Transactivator plants" contain CaMV ORF VI under the control of the strong
CaMV 35S promoter. The transactivator plants were difficult to regenerate
and showed an abnormal phenotype. Expression of GUS activity in the
reporter plants was very low, but high GUS activity could be induced by
introduction of gene VI, either by crossing with plants containing gene VI
as a transgene or by infection with CaMV. Histological GUS assays showed
that transactivation occurred in all types of tissue and at all
developmental stages. The practical implications of the induction of GUS
expression from the dicistronic unit by virus infection are discussed.
