Note from Alan Spradling
This vector that functions 4x better than pUASp. Notes from Alan Spradling: “A special UAS vector, UASp, was constructed in 1989 to allow GAL4::UAS expression in ovarian germ cells, but it is weak in somatic cells. As part of this research we generated a new UAS expression vector, UASz, that functions 4X better than UASp in the germline and as well, or almost as well, as UASt in somatic cells.