The Send1 coding sequence carried on an approximately 8 kb genomic fragment is precisely replaced with that of GAL4 resulting in a construct where a 4 kb Send1 upstream sequence regulates expression of a GAL4 driver.
Send1 reporter drives expression in the spermathecal secretory cells of virgin and mated females. It is visible by 20 hours post-eclosion and increases in intensity by day 4.