Adaptive Evolution of Eel Fluorescent Proteins from Fatty Acid Binding Proteins Produces Bright Fluorescence in the Marine Environment.
Adaptive Evolution of Eel Fluorescent Proteins from Fatty Acid Binding Proteins Produces Bright Fluorescence in the Marine Environment.
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DOI：
10.1371/journal.pone.0140972
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Pieribone VA
中科院分区：
文献类型：
--
作者：
Gruber DF;Gaffney JP;Mehr S;DeSalle R;Sparks JS;Platisa J;Pieribone VA
我们报道了来自海洋叶绿素鳗的胆红素诱导荧光蛋白（FPs）家族的两个新成员的鉴定和表征，并展示了该序列的一个关键区域，作为从非荧光到荧光脂肪酸结合蛋白（FABPs）的进化开关。通过对Kaupichthys eels （Kaupichthys hyoproides和Kaupichthys n. sp.）两种亮荧光鳗的转录组学分析，鉴定、克隆并鉴定了两个新的FP （Chlopsid FP I和Chlopsid FP II）。然后，我们对210个FABPs进行了系统发育分析，这些FABPs跨越16个脊椎动物目，包括163个脊椎动物分类群。我们发现荧光fp作为一个蛋白质家族分化，是脑FABPs的姐妹群。我们的研究结果表明，这个家族的进化涉及至少三个基因复制事件。我们发现荧光FABPs具有独特的，保守的三肽Gly-Pro-Pro序列基序，这在非荧光脂肪酸结合蛋白中没有发现。这个基序产生于FABP脑同工型的重复事件，并在强烈的净化选择下，导致这个新的FP家族的分类。与基序相邻的残基受到强烈的正选择，这表明鳗鱼蛋白的荧光特性进一步改进。我们提出了这一新兴FP家族的系统发育重建，并描述了来自远亲鳗鱼群体的其他荧光FABP成员。这类具有不同性质的鱼类FPs的阐明为基于蛋白质的荧光工具的开发提供了新的模板。从脂肪酸结合蛋白到荧光脂肪酸结合蛋白的进化适应，引起了人们对这种生活在蓝色、几乎单色海洋环境中的隐鳗属中亮绿色荧光的功能作用的兴趣。
We report the identification and characterization of two new members of a family of bilirubin-inducible fluorescent proteins (FPs) from marine chlopsid eels and demonstrate a key region of the sequence that serves as an evolutionary switch from non-fluorescent to fluorescent fatty acid-binding proteins (FABPs). Using transcriptomic analysis of two species of brightly fluorescent Kaupichthys eels (Kaupichthys hyoproroides and Kaupichthys n. sp.), two new FPs were identified, cloned and characterized (Chlopsid FP I and Chlopsid FP II). We then performed phylogenetic analysis on 210 FABPs, spanning 16 vertebrate orders, and including 163 vertebrate taxa. We show that the fluorescent FPs diverged as a protein family and are the sister group to brain FABPs. Our results indicate that the evolution of this family involved at least three gene duplication events. We show that fluorescent FABPs possess a unique, conserved tripeptide Gly-Pro-Pro sequence motif, which is not found in non-fluorescent fatty acid binding proteins. This motif arose from a duplication event of the FABP brain isoforms and was under strong purifying selection, leading to the classification of this new FP family. Residues adjacent to the motif are under strong positive selection, suggesting a further refinement of the eel protein’s fluorescent properties. We present a phylogenetic reconstruction of this emerging FP family and describe additional fluorescent FABP members from groups of distantly related eels. The elucidation of this class of fish FPs with diverse properties provides new templates for the development of protein-based fluorescent tools. The evolutionary adaptation from fatty acid-binding proteins to fluorescent fatty acid-binding proteins raises intrigue as to the functional role of bright green fluorescence in this cryptic genus of reclusive eels that inhabit a blue, nearly monochromatic, marine environment.