The influence of gene-environment interactions on GHR and IGF-I expression and their association with growth in brook charr, Salvelinus fontinalis (Mitchill)
The influence of gene-environment interactions on GHR and IGF-I expression and their association with growth in brook charr, Salvelinus fontinalis (Mitchill)
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DOI：
10.1186/1471-2156-8-87
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发表时间：
2007-12-21
期刊：
影响因子：
2.9
通讯作者：
Bernatchez, Louis
中科院分区：
文献类型：
--
作者：
Cote, Guillaume;Perry, Guy;Bernatchez, Louis
工作背景：定量反应规范理论认为，基因型与环境的相互作用（GxE）是由不同环境中适应性基因表达的个体间差异引起的。然而，实际基因组的环境规范很少有文献记载。在这项研究中，我们通过记录饲养环境的影响，研究了GxE相互作用对基因转录水平和生长的影响。（淡水与咸水）、性别和基因型（低与高估计育种值EBV）对布鲁克红点鲑胰岛素样生长因子（IGF-I）和生长激素受体（GHR）转录水平的影响结果：雄性比雌性长得快（雌性μ = 1.20 +/- 0.07 g中心点d（-1），μ雄性= 1.46 +/-0.06g中心点d（-1））和高EBV鱼比低EBV鱼快（μ（低）= 0.97 +/-0.05g中心点d（-1），mu（HIGH）= 1.58 +/-0.07 g中心点d（-1）; p < 0.05）。然而，盐水饲养的鱼类的生长明显低于淡水近亲（mu（FW）= 1.52 +/- 0.07 g中心点d（-1），mu（SW）= 1.15 +/- 0.06 g中心点d（-1）），但盐水中GHR mRNA转录水平显着高于淡水（mu（SW）= 0.85 +/- 0.05，μ（FW）= 0.61 +/- 0.05）。实际生长与测定的mRNA中的单位的比率（“个体转录效率”，iTE; g中心点d（-1）中心点u（-1））在EBV组之间也不同（μ（低）= 2.0 +/-0.24 g中心点d（-1）中心点u（-1）; mu（HIGH）= 3.7 +/- 0.24 g中心点d（-1）中心点u（-1））和环境（mu（SW）= 2.0 +/- 0.25 g中心点d（-1）中心点u（-1）; mu（FW）= 3.7 +/- 0.25 g中心点d（-1）中心点u（-1））。雄性GHR的iTE低于雌性（mu雄性= 2.4 +/- 0.29 g中心点d（-1）中心点u（-1）; mu雌性= 3.1 +/- 0.23 g中心点d（-1）中心点u（-1））。环境（p > 0.7）或EBV组（p > 0.15）之间的IGF-I转录水平没有差异，但雄性的IGF-I水平比雌性高4倍（mu雄性= 2.4 +/- 0.11，mu雌性= 0.58 +/- 0.09; p < 0.0001）。我们发现iTE存在显著的性别差异，（μ雄性= 1.3 +/- 0.59 g中心点d（-1）中心点u（-1）; μ雌性= 3.9 +/- 0.47 g中心点d（-1）中心点u（-1）），盐度（μ（SW）= 2.3 +/- 0.52 g中心点d（-1）中心点u（-1）; mu（FW）= 3.7 +/- 0.53 g中心点d（-1）中心点u（-1））和EB病毒组（mu（LOW）= 2.4 +/- 0.49 g中心点d（-1）中心点u（-1），mu（HIGH）= 3.8 +/- 0.49 g中心点d（-1）中心点u（-1））。两种GHR均检测到EBV群与环境的相互作用（p = 0.027）和IGF-I（p = 0.019），两个基因中的iTE（分别为p < 0.0001; p < 0.05），其中在盐水环境中，在EBV组之间发生GHR和IGF-I转录水平的增加的差异。我们的研究结果表明，环境和性别对参与生长生理途径的两个关键基因的mRNA表达有重大影响。我们还证明了第一次，至少在鱼类，基因型与环境的相互作用，在个人基因转录水平。这项工作大大有助于正在进行的努力，对记录环境和性诱导的基因活性的变化，并了解由此产生的表型。
Background: Quantitative reaction norm theory proposes that genotype-by-environment interaction (GxE) results from inter-individual differences of expression in adaptive suites of genes in distinct environments. However, environmental norms for actual gene suites are poorly documented. In this study, we investigated the effects of GxE interactions on levels of gene transcription and growth by documenting the impact of rearing environment (freshwater vs. saltwater), sex and genotypic (low vs. high estimated breeding value EBV) effects on the transcription level of insulin-like growth factor (IGF-I) and growth hormone receptor (GHR) in brook charr (Salvelinus fontinalis).Results: Males grew faster than females (mu female = 1.20 +/- 0.07 g center dot d(-1), mu male = 1.46 +/- 0.06 g center dot d(-1)) and high-EBV fish faster than low-EBV fish (mu(LOW) = 0.97 +/- 0.05 g center dot d(-1), mu(HIGH) = 1.58 +/- 0.07 g center dot d(-1); p < 0.05). However, growth was markedly lower in saltwater-reared fish than freshwater sibs (mu(FW) = 1.52 +/- 0.07 g center dot d(-1), mu(SW) = 1.15 +/- 0.06 g center dot d(-1)), yet GHR mRNA transcription level was significantly higher in saltwater than in freshwater (mu(SW) = 0.85 +/- 0.05, mu(FW) = 0.61 +/- 0.05). The ratio of actual growth to units in assayed mRNA ('individual transcript efficiency', iTE; g center dot d(-1) center dot u(-1)) also differed among EBV groups (mu(LOW) = 2.0 +/- 0.24 g center dot d(-1) center dot u(-1); mu(HIGH) = 3.7 +/- 0.24 g center dot d(-1) center dot u(-1)) and environments (mu(SW) = 2.0 +/- 0.25 g center dot d(-1) center dot u(-1); mu(FW) = 3.7 +/- 0.25 g center dot d(-1) center dot u(-1)) for GHR. Males had a lower iTE for GHR than females (mu male = 2.4 +/- 0.29 g center dot d(-1) center dot u(-1); mu female = 3.1 +/- 0.23 g center dot d(-1) center dot u(-1)). There was no difference in IGF-I transcription level between environments (p > 0.7) or EBV groups (p > 0.15) but the level of IGF-I was four times higher in males than females (mu male = 2.4 +/- 0.11, mu female = 0.58 +/- 0.09; p < 0.0001). We detected significant sexual differences in iTE (mu male = 1.3 +/- 0.59 g center dot d(-1) center dot u(-1); mu female = 3.9 +/- 0.47 g center dot d(-1) center dot u(-1)), salinities (mu(SW) = 2.3 +/- 0.52 g center dot d(-1) center dot u(-1); mu(FW) = 3.7 +/- 0.53 g center dot d(-1) center dot u(-1)) and EBV-groups (mu(LOW) = 2.4 +/- 0.49 g center dot d(-1) center dot u(-1), mu(HIGH) = 3.8 +/- 0.49 g center dot d(-1) center dot u(-1)). Interaction between EBV-group and environment was detected for both GHR (p = 0.027) and IGF-I (p = 0.019), and for iTE in the two genes (p < 0.0001; p < 0.05, respectively), where increased divergence in levels of GHR and IGF-I transcription occurred among EBV-groups in the saltwater environment.Conclusion: Our results show that both environment and sex have major impacts on the expression of mRNA for two key genes involved in the physiological pathway for growth. We also demonstrate for the first time, at least in fish, genotype-by-environment interaction at the level of individual gene transcription. This work contributes significantly to ongoing efforts towards documenting environmentally and sexually induced variance of gene activity and understanding the resulting phenotypes.