Candida famata is a representative of a group of so‐called flavinogenic yeast species that overproduce riboflavin (vitamin B₂) in response to iron limitation. Overproduced riboflavin accumulates in the cultural medium rather than in the cells suggesting existence of the special mechanisms involved in riboflavin excretion. The corresponding protein and gene have not been identified in yeasts. At the same time, the corresponding gene BCRP has been identified in mammal mammary glands. Several homologs of the mammal BCRP gene encoding putative riboflavin efflux protein (excretase) were identified in Debaryomyces hansenii. The closest homolog was expressed under the control of D. hansenii TEF1 promoter in the riboflavin overproducing strain of C. famata. Resulted transformants overexpressed the corresponding gene and produced 1.4‐ to 1.8‐fold more riboflavin as compared with the parental strain. They also were characterized by overexpression of RIB1 and RIB6 genes of riboflavin synthesis and exhibited elevated specific activity of GTP‐cyclohydrolase II. Membrane localization of the riboflavin excretase was confirmed by fluorescent microscopy.

中文翻译：

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编码核黄素外排蛋白的哺乳动物 BCRP 基因的酵母同源物的表达激活了产黄素酵母念珠菌中维生素 B2 的产生。

念珠菌是一组所谓的黄素酵母菌的代表，这些酵母菌因铁限制而过量产生核黄素（维生素 B ₂）。过量产生的核黄素在培养基中而不是在细胞中积累，表明存在参与核黄素排泄的特殊机制。尚未在酵母中鉴定出相应的蛋白质和基因。同时，在哺乳动物乳腺中已鉴定出相应的基因BCRP。在汉森德巴利酵母中鉴定了编码推定核黄素外排蛋白（排泄酶）的哺乳动物BCRP基因的几个同源物。最接近的同源物在D. hansenii TEF1的控制下表达 C. famata核黄素过量生产菌株中的启动子。与亲本菌株相比，所得转化体过度表达相应基因并产生多 1.4 至 1.8 倍的核黄素。它们的特征还在于核黄素合成的RIB1和RIB6基因的过度表达，并表现出GTP-环化水解酶 II 的比活性升高。核黄素排泄酶的膜定位通过荧光显微镜检查证实。