Institute for Marine Biosciences, National Research Council, Halifax, NS, Canada.
Mar Biotechnol (NY). 2010 Nov;12(6):650-63. doi: 10.1007/s10126-009-9252-8. Epub 2010 Jan 27.
Rainbow smelt (Osmerus mordax) are freeze-resistant fish that accumulate glycerol and produce an antifreeze protein during winter. Quantitative reverse transcription PCR (qPCR) and subtractive hybridization studies have previously revealed five genes in rainbow smelt liver to be differentially regulated in winter in comparison with the fall when water temperatures are warmer. In order to further define the suite of processes that are regulated seasonally, we undertook a large-scale analysis of gene expression by hybridization of smelt cDNA to the salmonid 16K cGRASP microarray. In total, 69 genes were identified as up-regulated and 14 genes as down-regulated under winter conditions. A subset of these genes was examined for differential regulation by qPCR in the individual cDNA samples that were pooled for microarray analysis. Ten of the 15 genes tested showed significant change in the same direction as microarray results, whereas one showed significant change in the opposite direction. Fructose-bisphosphate aldolase B and the cytosolic NAD-dependent glycerol-3-phosphate dehydrogenase were among the most highly up-regulated genes, a result supporting a metabolic focus on glycerol synthesis during winter. Modulation of other processes, including endoplasmic reticulum stress, lipid metabolism and transport, and protein synthesis, was also suggested by the qPCR analysis of array-identified genes. The 15 genes were subsequently examined by qPCR for seasonal variation in expression over five sampling times between October and March, and ten showed significant variation in expression over the sampling period. Taken together, these results provide new understanding of the biochemical adaptations of vertebrates to an extremely low seasonal temperature.
虹鳟（Osmerus mordax）是一种抗冻鱼类，在冬季会积累甘油并产生抗冻蛋白。定量逆转录 PCR（qPCR）和差减杂交研究表明，与水温较高的秋季相比，虹鳟肝脏中的五个基因在冬季会发生差异调节。为了进一步确定受季节性调节的一系列过程，我们通过将虹鳟 cDNA 与鲑鱼 16K cGRASP 微阵列杂交，对基因表达进行了大规模分析。总共鉴定出 69 个基因在冬季上调，14 个基因下调。对这些基因中的一部分进行了 qPCR 检测，以验证其在用于微阵列分析的 cDNA 样本中的差异调节。在测试的 15 个基因中，有 10 个基因的变化方向与微阵列结果一致，而有 1 个基因的变化方向相反。果糖二磷酸醛缩酶 B 和细胞质 NAD 依赖性甘油-3-磷酸脱氢酶是上调最明显的基因之一，这一结果支持了冬季甘油合成代谢的焦点。qPCR 分析表明，其他过程的调节，包括内质网应激、脂质代谢和运输以及蛋白质合成，也得到了证实。随后，对这 15 个基因进行 qPCR 检测，以了解它们在 10 月至 3 月 5 次采样期间的季节性表达变化，其中 10 个基因在采样期间的表达存在显著差异。综上所述，这些结果为脊椎动物对极低季节性温度的生化适应提供了新的认识。
