Part:BBa_K3970002

TURA3 gene is a gene on chromosome V of yeast, whose systematic name is YEL021W. It encodes the whyside 5-phosphate decarboxylase, an enzyme that catalyzes one of the key reactions in the synthesis of pyrimidine nucleotides from yeast RNA.The whyside 5-phosphate decarboxylase is inactivated and the yeast cannot grow unless uridine or uracil is added to the medium.If you were to nutrient transformation into URA3 gene defects strains, as these nutritional deficiencies plants can grow (positive), on the contrary, if you add 5- to medium FOA (5-fluorine orotic acid), then the original keep normal type yeast cells of whey 5-phosphoric acid decarboxylase can convert 5-FOA into toxic substances, (suicide inhibitor) and its product,5-fluorouracil can cause cell death (negative selection).   Because URA3 gene can carry out both positive and negative selection, it has become a genetic marker, which is widely used in gene transformation and other genetic experiments of bacteria and many kinds of fungi.It is also one of the most important genetic markers (reporter genes) in yeast genetic engineering.