Keenan Sarah W, Hill Craig A, Kandoth Cyriac, Buck Leslie T, Warren Daniel E
Department of Biology, Saint Louis University, St. Louis, Missouri, United States of America.
The Genome Institute, Washington University School of Medicine, St. Louis, Missouri, United States of America.
PLoS One. 2015 Jul 6;10(7):e0131669. doi: 10.1371/journal.pone.0131669. eCollection 2015.
Painted turtles are the most anoxia-tolerant tetrapods known, capable of surviving without oxygen for more than four months at 3°C and 30 hours at 20°C. To investigate the transcriptomic basis of this ability, we used RNA-seq to quantify mRNA expression in the painted turtle ventricle and telencephalon after 24 hours of anoxia at 19°C. Reads were obtained from 22,174 different genes, 13,236 of which were compared statistically between treatments for each tissue. Total tissue RNA contents decreased by 16% in telencephalon and 53% in ventricle. The telencephalon and ventricle showed ≥ 2x expression (increased expression) in 19 and 23 genes, respectively, while only four genes in ventricle showed ≤ 0.5x changes (decreased expression). When treatment effects were compared between anoxic and normoxic conditions in the two tissue types, 31 genes were increased (≥ 2x change) and 2 were decreased (≤ 0.5x change). Most of the effected genes were immediate early genes and transcription factors that regulate cellular growth and development; changes that would seem to promote transcriptional, translational, and metabolic arrest. No genes related to ion channels, synaptic transmission, cardiac contractility or excitation-contraction coupling changed. The generalized expression pattern in telencephalon and across tissues, but not in ventricle, correlated with the predicted metabolic cost of transcription, with the shortest genes and those with the fewest exons showing the largest increases in expression.
彩龟是已知最耐缺氧的四足动物,能够在3℃下无氧存活四个多月,在20℃下无氧存活30小时。为了研究这种能力的转录组学基础,我们使用RNA测序来量化彩龟在19℃下缺氧24小时后心室和端脑中mRNA的表达。从22,174个不同基因中获得了读数,其中13,236个基因在每个组织的不同处理之间进行了统计学比较。端脑的总组织RNA含量下降了16%,心室下降了53%。端脑和心室分别在19个和23个基因中表现出≥2倍的表达(表达增加),而心室中只有4个基因表现出≤0.5倍的变化(表达减少)。当比较两种组织类型在缺氧和常氧条件下的处理效果时,31个基因表达增加(≥2倍变化),2个基因表达减少(≤0.5倍变化)。大多数受影响的基因是调节细胞生长和发育的即早基因和转录因子;这些变化似乎会促进转录、翻译和代谢停滞。与离子通道、突触传递、心脏收缩力或兴奋-收缩偶联相关的基因没有变化。端脑和跨组织(但不是心室)的普遍表达模式与预测的转录代谢成本相关,最短的基因和外显子最少的基因表达增加幅度最大。