Vuori Kristiina A M, Koskinen Heikki, Krasnov Aleksei, Koivumäki Paula, Afanasyev Sergey, Vuorinen Pekka J, Nikinmaa Mikko
Centre of Exellence in Evolutionary Genetics and Physiology, Department of Biology, University of Turku, FI-20014 Turku, Finland.
BMC Genomics. 2006 Mar 17;7:56. doi: 10.1186/1471-2164-7-56.
We have studied alterations of gene expression associated with naturally-occurring early life stage mortality (M74) in Baltic salmon using a cDNA microarray and real time PCR. M74-affected fry have several typical neurological, cardiovascular and pathological symptoms. They are also characterized by low thiamine content and show signs of oxidative stress.
Affected fry can be divided into three major groups with early, intermediate or late onset of mortality. If mortality starts during the first third of the yolk-sac stage, virtually all the responses are compatible with stress, which rapidly leads to the common terminal responses. If death occurs during the second third of the yolk sac stage, the terminal stage is preceded by a decrease in globin gene expression, which leads to internal hypoxia when the animals grow and shift from skin- to gill-breathing. Fry will eventually proceed to the terminal responses. The group developing M74 most slowly appears to compensate for reduced oxygen delivery by downregulation of metabolism, and hence some fry can escape death.
Our study is the first demonstration of diverse transcriptional responses to a naturally-occurring developmental disturbance. Since many of the genes differentially expressed in M74-fry are evolutionarily conserved, the M74 of Baltic salmon can serve as a model for developmental disturbances and environmental stress responses in vertebrates in general.
我们利用cDNA微阵列和实时定量PCR技术，研究了波罗的海鲑鱼自然发生的早期生命阶段死亡（M74）相关的基因表达变化。受M74影响的鱼苗有几种典型的神经、心血管和病理症状。它们还具有硫胺素含量低的特点，并表现出氧化应激的迹象。
受影响的鱼苗可分为三个主要组，分别为早期、中期或晚期死亡。如果死亡发生在卵黄囊期的前三分之一时间内，几乎所有的反应都与应激有关，这会迅速导致共同的终末反应。如果死亡发生在卵黄囊期的中间三分之一时间内，在终末期之前，珠蛋白基因表达会下降，当动物生长并从皮肤呼吸转变为鳃呼吸时，这会导致体内缺氧。鱼苗最终会进入终末反应阶段。M74发展最慢的一组鱼苗似乎通过下调代谢来补偿氧气供应的减少，因此一些鱼苗能够逃脱死亡。
我们的研究首次证明了对自然发生的发育障碍存在多种转录反应。由于在受M74影响的鱼苗中差异表达的许多基因在进化上是保守的，波罗的海鲑鱼的M74总体上可作为脊椎动物发育障碍和环境应激反应的模型。
