Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, PO Box 5030, Atlanta, GA 30302-5030, United States.
Gen Comp Endocrinol. 2011 Jan 15;170(2):408-14. doi: 10.1016/j.ygcen.2010.10.021. Epub 2010 Nov 2.
Coactivator proteins, such as steroid receptor coactivator-1 (SRC-1) greatly enhance gene expression by amplifying steroid-induced transcription regulated by receptors such as estrogen receptor. These proteins may also play a role in the development of sex differences in central nervous system as well the maintenance of the sexually dimorphic behaviors in adulthood. One well-studied sexually dimorphic behavior is singing in songbirds such as the Australian zebra finch (Taeniopygia guttata). Song learning and production is controlled by the song control system, a collection of sexually dimorphic nuclei found in the avian telencephalon. While the actions of steroid hormones on song nuclei development has been under debate, steroids, such as testosterone, influence singing behavior in adulthood. We hypothesize that the differential expression of coactivators in male and female brains aid in organizing the song nuclei during development and function in adulthood to aid in activating the song control nuclei to induce singing behavior. The distribution of SRC-1-immunoreactive neurons was localized in the brains of male and female zebra finches on the day of hatch (P1) and in adults. In adults SRC-1 immunoreactive cells are found in the four main song control nuclei as well as other steroid sensitive brain regions. We found that SRC-1 is sexually dimorphic in the adult zebra finch telencephalon, suggesting that coactivators may play a role in the maintenance of sexually dimorphic behaviors including singing.
共激活蛋白，如甾体激素受体共激活蛋白-1（SRC-1），通过放大甾体激素受体（如雌激素受体）调节的转录，极大地增强了基因表达。这些蛋白质在中枢神经系统性别差异的发展以及成年期性别二态性行为的维持中也可能发挥作用。一种研究得很好的性别二态性行为是鸣禽（如澳大利亚斑马雀（Taeniopygia guttata））的鸣叫。鸣禽学习和发声由歌唱控制系统控制，该系统是鸟类端脑中发现的一组性别二态性核团。虽然甾体激素对歌唱核团发育的作用一直存在争议，但甾体激素，如睾酮，会影响成年期的歌唱行为。我们假设，雄性和雌性大脑中共激活蛋白的差异表达有助于在发育过程中组织歌唱核团，并在成年期发挥作用，以激活歌唱控制系统核团，从而诱导歌唱行为。SRC-1 免疫反应性神经元的分布在孵化日（P1）和成年期雄性和雌性斑马雀的大脑中进行了定位。在成年期，SRC-1 免疫反应性细胞存在于四个主要的歌唱控制核团以及其他甾体激素敏感的脑区。我们发现，SRC-1 在成年斑马雀端脑中存在性别二态性，这表明共激活蛋白可能在维持包括鸣叫在内的性别二态性行为中发挥作用。
