Upstream regulatory regions from the maize Sh1 promoter confer tissue specific expression of the beta-glucuronidase gene in tomato

A promoter fusion (Sh35) combining upstream regulatory regions from the mai ze Sh1 promoter with a truncated 35S promoter, Delta 9035 (-90 to +8) has b een compared with the original Sh1 promoter for its capacity to promote exp ression of the beta-glucuronidase (GUS) gene in stably transformed tomato p lants. For both promoters, very faint GUS expression was detected in the ve getative tissues, and no expression was detected in the fruit pericarp tiss ues. However, in the seed, Sh1 promoted low GUS expression but Sh35 directe d 25-fold higher GUS expression. For both constructs, the profile of GUS ex pression was similar to that of endogenous sucrose synthase activity but ma ximal GUS activity was reached 15 days after the peak of sucrose synthase a ctivity.