Kirchner S, McDaniel N K, Sugiura S H, Soteropoulos P, Tian B, Fletcher J W, Ferraris R P
Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey (UMDNJ), New Jersey Medical School, Newark, NJ 07103-2714, USA.
Anim Genet. 2007 Aug;38(4):319-31. doi: 10.1111/j.1365-2052.2007.01615.x. Epub 2007 Jun 26.
Nutrient-responsive genes can identify important metabolic pathways and evaluate optimal dietary levels. Using a 16K Salmo salar microarray, we identified in rainbow trout (Oncorhynchus mykiss) 21 potential phosphorus (P)-responsive genes, mainly involved in immune response, proteolysis or transport, whose expression levels changed in the intestine after 5 days of feeding a low-P (LP) diet. Diet-induced changes in the expression levels of several genes in each fish were tightly correlated with changes in serum P, and the changes persisted for an additional 15 days after dietary P deficiency. We then evaluated these and previously identified P-responsive genes under simulated farm conditions, and monitored the intestinal gene expression from 6 h to 7 days after the trout were switched from a sufficient-P (SP) diet to a LP diet (SP-->LP), and from a LP diet to a SP diet (LP-->SP). After 7 days, mean serum P decreased 0.14 mM/day for SP-->LP and increased 0.10 mm/day for LP-->SP. The mRNA abundance of the metalloendopeptidase meprin 1alpha (MEP1alpha), the Na(+)-dependent phosphate co-transporter (NaPi2b,SLC34A2), the sulfotransferase SULT2beta1 and carbonic anhydrase XIII genes all increased after SP-->LP and decreased after LP-->SP, suggesting that adaptive expression is reversible and correlated with dietary P. The duration of change in gene expression in response to SP-->LP was generally shorter than that of LP-->SP, suggesting potentially different mechanisms of adaptation to deficiency as opposed to excess. Diet-induced changes in mRNA abundance of other genes were either transient or modest. We identified, by heterologous microarray hybridization, new genes sensitive to perturbations in dietary P, and then showed that these genes can reliably monitor P deficiency under field conditions. Simultaneous changes in the expression of these P biomarkers could predict either P deficiency (to prevent economic losses to the farmers) or P excess (to prevent inadvertent pollution of nearby waters).
营养响应基因能够识别重要的代谢途径并评估最佳饮食水平。我们使用16K的大西洋鲑鱼微阵列，在虹鳟鱼（Oncorhynchus mykiss）中鉴定出21个潜在的磷（P）响应基因，这些基因主要参与免疫反应、蛋白水解或转运过程，在投喂低磷（LP）日粮5天后，其在肠道中的表达水平发生了变化。日粮诱导的每条鱼中几个基因表达水平的变化与血清磷的变化紧密相关，并且在日粮缺磷后这些变化持续了另外15天。然后，我们在模拟养殖条件下评估了这些以及先前鉴定出的磷响应基因，并监测了虹鳟鱼从充足磷（SP）日粮转换为LP日粮（SP→LP）以及从LP日粮转换为SP日粮（LP→SP）后6小时至7天内肠道基因的表达情况。7天后，对于SP→LP，平均血清磷每天下降0.14 mM，对于LP→SP，平均血清磷每天升高0.10 mM。金属内肽酶meprin 1α（MEP1α）、钠依赖性磷酸盐共转运体（NaPi2b，SLC34A2）、磺基转移酶SULT2β1和碳酸酐酶XIII基因的mRNA丰度在SP→LP后均升高，在LP→SP后均降低，这表明适应性表达是可逆的且与日粮磷相关。响应SP→LP的基因表达变化持续时间通常比LP→SP的短，这表明适应缺磷与适应磷过量的机制可能不同。日粮诱导的其他基因mRNA丰度变化要么是短暂的，要么是适度的。我们通过异源微阵列杂交鉴定出对日粮磷扰动敏感的新基因，然后表明这些基因能够在田间条件下可靠地监测磷缺乏情况。这些磷生物标志物表达的同时变化可以预测磷缺乏（以防止农民遭受经济损失）或磷过量（以防止对附近水域的意外污染）。
