Lee Kang-Min, Daubnerová Ivana, Isaac R Elwyn, Zhang Chen, Choi Sekyu, Chung Jongkyeong, Kim Young-Joon
School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea.
School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
Curr Biol. 2015 Mar 16;25(6):790-797. doi: 10.1016/j.cub.2015.01.050. Epub 2015 Feb 19.
In polyandrous females, sperm storage permits competition between sperm of different mates, and in some species females influence the relative fertilization success of competing sperm in favor of a preferred mate [1, 2]. In female Drosophila melanogaster, sperm competition is strongly influenced by the timing of sperm ejection from the uterus [3, 4]. Understanding how female behavior influences sperm competition requires knowledge of the neuronal mechanisms controlling sperm retention and storage, which is currently lacking. Here, we show that D. melanogaster females eject male ejaculates from the uterus 1-6 hr after mating with a stereotypic behavior regulated by a brain signaling pathway composed of diuretic hormone 44 (Dh44), a neuropeptide related to vertebrate corticotropin-releasing factor (CRF), and its receptor, Dh44R1. Suppression of Dh44 signals in the brain expedites sperm ejection from the uterus, resulting in marked reduction of sperm in the storage organs and decreased fecundity, whereas enhancement of Dh44 signals delays sperm expulsion. The Dh44 function was mapped to six neurons located in the pars intercerebralis of the brain together with a small subset of Dh44R1 neurons that express the sex-specific transcription factor doublesex. This study identifies a neuronal pathway by which females can control sperm retention and storage and provides new insight into how the female might exercise post-copulatory sexual selection.
在一妻多夫制的雌性动物中，精子储存允许不同配偶的精子之间进行竞争，并且在某些物种中，雌性会影响竞争精子的相对受精成功率，使其有利于偏好的配偶[1,2]。在雌性黑腹果蝇中，精子竞争受到子宫中精子排出时间的强烈影响[3,4]。了解雌性行为如何影响精子竞争需要掌握控制精子保留和储存的神经机制，而目前这方面的知识还很缺乏。在这里，我们表明，黑腹果蝇雌性在交配后1-6小时会通过一种由利尿激素44（Dh44）组成的脑信号通路调节的刻板行为，从子宫中排出雄性射精物。Dh44是一种与脊椎动物促肾上腺皮质激素释放因子（CRF）相关的神经肽，及其受体Dh44R1。抑制脑中的Dh44信号会加速精子从子宫中排出，导致储存器官中的精子显著减少，并降低繁殖力，而增强Dh44信号则会延迟精子排出。Dh44的功能定位于位于脑间部的六个神经元以及一小部分表达性别特异性转录因子双性的Dh44R1神经元。这项研究确定了一条雌性可以控制精子保留和储存的神经通路，并为雌性如何进行交配后性选择提供了新的见解。
