THE PLANT CELL, Vol 9, Issue 11 2025-2036, Copyright © 1997 by American Society of Plant Biologists
A Strong Inhibitor of Gene Expression in the 5[prime] Untranslated Region of the Pollen-Specific LAT59 Gene of Tomato
C. Curie and S. McCormick
Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service and University of California at Berkeley, 800 Buchanan Street, Albany, California 94710
Promoter sequences that direct pollen-specific expression have been
previously identified in the LAT59 (for late anther tomato) gene. Here, we
show that the LAT59 sequences encoding the 5[prime] untranslated region
inhibit expression of reporter genes by >20-fold in transient expression
experiments and up to 300-fold after stable transformation. Inhibition
occurred in somatic cells as well as in pollen. Our results indicate that
the inhibitor still functions after pollen germination and therefore does
not modulate the level of the LAT59 protein during pollen development. The
presence of the leader sequence dramatically decreased mRNA accumulation
but without affecting translation rate and mRNA stability. We believe that
the leader inhibits transcription. We mapped the inhibitor to a region in
the leader that coincides with a putative stem-loop and present evidence
that this stem-loop participates in inhibition.
