UASp regulatory sequences drives expression of full-length Ecol\birA. The coding sequence is tagged at the N-terminal end with the Tag:SS(ea) signal sequence and at the C-terminal end with a KEEL endoplasmic reticulum (ER)retention signal; despite the presence of the KEEL signal the protein is not retained in the ER when expressed using a maternal driver (it was not possible to determine whether or not the protein is secreted into the perivitelline space).