원문정보
초록
영어
Phosphate starvation is a major nutritional problem faced by microorganisms in many ecosystems. This starvation results in altered gene expression leading to physiological changes in microorganisms. Then, when the microorganisms encounter phosphate starvation stress, it responds by inducing genes that function to restrict the metabolic consequences of the limited supply of this essential nutrient. Transcriptional activities of these genes have been known to be regulated by phosphate. Therefore, the promoter from phosphate-starvation-inducible gene can be used as an alternative promoter to constitutive or inducible promoter requiring an inducer. We analyzed the overexpressed genes in the phosphate-limited continuous culture of Pichia pastoris at transcriptional level. Among these genes, the gene with high homology to Na+-coupled phosphate symporter (NPS) was cloned. The putative NPS from P. pastoris revealed an open reading frame of 1,731 bp with the potential to encode a polypeptide of 576 amino acids with a calculated mass of 63 kDa. The potential of the promoter (PNPS) in P. pastoris was investigated by using a bacterial lipase gene as a reporter gene. PNPS is controlled by the phosphate concentration in the medium and is highly activated when the cells are under the phosphate-limiting conditions. We thought that the phosphate-starvation-inducible PNPS will be a useful promoter for heterologous gene in P. pastoris.