Trp1 vs. Leu2 vectors.

[David Perez-Morga]

	Hello everybody,
	I have a yeast strain (trp1-, leu2-, his3-, ade2-, lys2-) that I have
transformed with plasmids harboring the TRP1 or LEU2 genes (i. e. as in
the two hybrid system). When I transform with the LEU2 plasmid alone or
together with the TRP1, I get high efficiencies of transformation
(10e6/ug), but, when I transform the same strain with the TRP1 plasmid
alone I get a very low efficiency (10e2/ug).
	Could anybody explain to me why?. 




					David Perez-Morga

					Labo. de Parasitologie Moleculaire
					Departement de Biologie Moleculaire
					Universite Libre de Bruxelles
					Rue des Chevaux 65
					1640 Rhode-St.-Genese 
					BELGIQUE

					Tel: (32-2) 650.9636
					Fax: (32-2) 650.9656

					e-mail: dperez at alize.ulb.ac.be