Bansal Saumya, Luu Bryan E, Storey Kenneth B
Institute of Biochemistry, Carleton University, Ottawa, ON, K1S 5B6, Canada.
J Comp Physiol B. 2016 Feb;186(2):229-41. doi: 10.1007/s00360-015-0951-3. Epub 2015 Dec 11.
The North American wood frog, Rana sylvatica, is one of just a few anuran species that tolerates whole body freezing during the winter and has been intensely studied to identify the biochemical adaptations that support freeze tolerance. Among these adaptations is the altered expression of many genes, making freeze-responsive changes to gene regulatory mechanisms a topic of interest. The present study focuses on the potential involvement of microRNAs as one such regulatory mechanism and aims to better understand freeze/thaw stress-induced microRNA responses in the freeze-tolerant wood frog. Using quantitative PCR, relative levels of 53 microRNAs were measured in heart and skeletal muscle of control, 24 h frozen, and 8 h thawed frogs. MicroRNAs showed tissue specific expression patterns: 21 microRNAs decreased in the heart during thawing, whereas 16 microRNAs increased during freezing stress in skeletal muscle. These findings suggest that select genes may be activated and suppressed in heart and skeletal muscle, respectively, in response to freezing. Bioinformatics analysis using the DIANA miRPath program (v.2.0) predicted that the differentially expressed microRNAs may collectively regulate tissue-specific cellular pathways to promote survival of wood frogs undergoing freezing and thawing.
北美林蛙（Rana sylvatica）是少数几种能够在冬季耐受全身冻结的蛙类物种之一，人们对其进行了深入研究，以确定支持耐冻性的生化适应机制。在这些适应机制中，许多基因的表达发生了改变，这使得基因调控机制的冻融反应变化成为一个研究热点。本研究聚焦于微小RNA作为一种调控机制的潜在作用，旨在更好地理解耐冻林蛙中冻融应激诱导的微小RNA反应。通过定量PCR，测定了对照蛙、冷冻24小时的蛙和解冻8小时的蛙的心脏和骨骼肌中53种微小RNA的相对水平。微小RNA呈现出组织特异性表达模式：21种微小RNA在解冻过程中心脏中减少，而16种微小RNA在骨骼肌冷冻应激期间增加。这些发现表明，在冷冻过程中，特定基因可能分别在心脏和骨骼肌中被激活和抑制。使用DIANA miRPath程序（v.2.0）进行的生物信息学分析预测，差异表达的微小RNA可能共同调节组织特异性细胞途径，以促进经历冻融的林蛙的存活。
