Table 1.

List of different regulatory elements used to design a set of gag piggyBac vector constructs.

Construct	Enhancer	Promoter	Intron upstream	Gene	Intron downstream	PolyA	Final pXLBacII construct
pHSP70		Drosophila hsp70		gag		SV40sti/polyA	pXLHSP70Gag
pIE1	hr5	Baculovirus AcMNPV ie1		gag		(Heliothis) hel2polyA	pXLIE1Gag
pIE1	hr5	Baculovirus AcMNPV ie1		Neo		hel2polyA	pXLNeo
pIE1-SV	hr5	Baculovirus AcMNPV ie1		gag		SV40sti/polyA	pXLIE-SVGag
pActin		Drosophila actin 5C		gag		hel2-polyA	pXLActinGag
pActin-SV		Drosophila actin 5C		gag		SV40sti/polyA	pXLActin-SVGag
409-FOR	hr5	Baculovirus AcMNPV ie1	+	gag		hel2polyA	pXL409Gag
410-FOR	hr5	Baculovirus AcMNPV ie1		gag	+	hel2polyA	pXL410Gag
411-FOR		Drosophila actin 5C	+	gag		hel2-polyA	pXL411Gag
412-FOR		Drosophila actin 5C		gag	+	hel2-polyA	pXL412Gag
Hr3ieLuc	hr3	Baculovirus AcMNPV ie1		gag			pXlHr3ieGag
pBSII-IE1-orf		Baculovirus AcMNPV ie1		gag		pBSII-IE1-orf polyA	pXLBSII-IE1Gag

The promoters tested included Drosophila hsp70, AcMNPV ie1 and Drosophila actin 5C [30,31] (column 3). The promoter enhancers used were hr5 [31] and hr3 [30] (column 2). Poly-adenylation (polyA) sequences included SV40sti/polyA, hel2polyA [31] and a polyA tail isolated from the pBSII-IE1-orf helper plasmid [14,15] (column 7). 409-FOR and 410-FOR are pIE1 vectors containing a 133 bp intron [32] (column 4 and 6) upstream or downstream of the gag gene, respectively. 411-FOR and 412-FOR are pActin vectors containing the intron upstream or downstream of the gag gene, respectively. Briefly, different promoters, enhancers, polyA sequences or the intron were removed from the construct described in column 1 and coupled to gag in the transposable pXLBacII vector [14,15] (column 8).