ninaED1, a dominant allele
of the major Drosophila rhodopsin gene, expresses
a rhodopsin that is predominantly recovered in a 80-kD
complex that likely represents rhodopsin dimers. By driving
either ninaED1 or ninaE+
expression from a heat-shock promoter, we show that the
80-kD rhodopsin complex forms immediately after gene activation.
In wild type, but not ninaED1, rhodopsin
monomeric forms are detected at later times. The generation
of monomeric forms of wild-type rhodopsin is suppressed
in vitamin A-deprived flies or in flies heterozygous for
the dominant rhodopsin mutation. We also show that ninaED1
expression does not affect the maturation of another Drosophila
visual pigment, Rh3. These results are consistent with
the view that the ninaED1 rhodopsin
antagonizes an early posttranslation process that is specific
for maturation of the ninaE-encoded rhodopsin.