Background

Lasting changes in gene expression in brain reward regions, including nucleus accumbens (NAc), contribute to persistent functional changes in the addicted brain. We and others have demonstrated that altered expression of several candidate transcription factors in NAc regulates drug responses. A recent large-scale genome-wide study from our group predicted E2F3 as a prominent upstream regulator of cocaine-induced changes in gene expression and alternative splicing.

Methods

We studied the expression of two E2F3 isoforms – E2F3a and E2F3b – in mouse NAc after repeated cocaine administration, and assayed the effects of overexpression or depletion of E2F3 isoforms in NAc on cocaine behavioral responses. We then performed RNA-seq to investigate the effect of E2F3a overexpression in this region on gene expression and alternative splicing, performed qChIP at downstream targets in NAc following E2F3a overexpression or repeated cocaine exposure. Sample sizes vary between experiments and are noted in the text.

Results

We show that E2F3a, but not E2F3b, overexpression in mouse NAc regulates cocaine-induced locomotor and place conditioning behavior. Furthermore, we demonstrate that E2F3a overexpression substantially recapitulates genome-wide transcriptional profiles and alternative splicing induced by cocaine. We further validate direct binding of E2F3a at key target genes following cocaine exposure.

Conclusions

This study establishes E2F3a as a novel transcriptional regulator of cocaine action in NAc. The findings reveal a crucial role for E2F3a in the regulation of cocaine-elicited behavioral states. Moreover, the importance of this role is bolstered by the extensive recapitulation of cocaine’s transcriptional effects in NAc upon expression of E2F3a.

中文翻译：

---

伏伏核中的E2F3a通过转录和选择性剪接影响可卡因的作用

背景

包括伏伏核（NAc）在内的大脑奖励区域中基因表达的持久变化有助于上瘾的大脑持续发生功能变化。我们和其他人证明，NAc中几种候选转录因子的表达改变会调节药物反应。我们小组最近进行的一项大规模的全基因组研究预测E2F3是可卡因诱导的基因表达变化和可变剪接的重要上游调控因子。

方法

我们研究了重复给予可卡因后在小鼠NAc中两种E2F3亚型-E2F3a和E2F3b的表达，并分析了NAc中E2F3亚型的过表达或耗竭对可卡因行为反应的影响。然后，我们进行了RNA测序，以研究E2F3a在该区域中过表达对基因表达和选择性剪接的影响，在E2F3a过表达或可卡因反复暴露后，在NAc的下游靶点上进行qChIP。实验之间的样本量各不相同，并在正文中注明。

结果

我们显示E2F3a，但不是E2F3b，在小鼠NAc中的过表达调节可卡因诱导的运动和位置调节行为。此外，我们证明E2F3a过表达基本上概括了可卡因诱导的全基因组转录谱和选择性剪接。我们进一步验证了可卡因暴露后，E2F3a在关键靶基因上的直接结合。

结论

这项研究建立了E2F3a作为NAc中可卡因作用的新型转录调节因子。这些发现揭示了E2F3a在可卡因引起的行为状态调节中的关键作用。此外，在表达E2F3a后，NAc中可卡因的转录作用的广泛概括进一步证明了这一作用的重要性。