Research Institute of Molecular Pathology, A-1030 Vienna, Austria.
Proc Natl Acad Sci U S A. 2010 Apr 6;107(14):6520-5. doi: 10.1073/pnas.0914764107. Epub 2010 Mar 22.
Upon mating, females of many animal species undergo dramatic changes in their behavior. In Drosophila melanogaster, postmating behaviors are triggered by sex peptide (SP), which is produced in the male seminal fluid and transferred to female during copulation. SP modulates female behaviors via sex peptide receptor (SPR) located in a small subset of internal sensory neurons that innervate the female uterus and project to the CNS. Although required for postmating responses only in these female sensory neurons, SPR is expressed broadly in the CNS of both sexes. Moreover, SPR is also encoded in the genomes of insects that lack obvious SP orthologs. These observations suggest that SPR may have additional ligands and functions. Here, we identify myoinhibitory peptides (MIPs) as a second family of SPR ligands that is conserved across a wide range of invertebrate species. MIPs are potent agonists for Drosophila, Aedes, and Aplysia SPRs in vitro, yet are unable to trigger postmating responses in vivo. In contrast to SP, MIPs are not produced in male reproductive organs, and are not required for postmating behaviors in Drosophila females. We conclude that MIPs are evolutionarily conserved ligands for SPR, which are likely to mediate functions other than the regulation of female reproductive behaviors.
许多动物物种的雌性在交配后会经历行为的剧烈变化。在黑腹果蝇中，交配后的行为是由性肽 (SP) 触发的，SP 是在雄性精液中产生的，并在交配时传递给雌性。SP 通过位于内部感觉神经元中的一小部分中的性肽受体 (SPR) 来调节雌性行为，这些神经元支配着雌性的子宫并投射到中枢神经系统。尽管 SPR 仅在这些雌性感觉神经元中对交配后的反应是必需的，但 SPR 在两性的中枢神经系统中广泛表达。此外，SPR 也编码在缺乏明显 SP 同源物的昆虫基因组中。这些观察结果表明，SPR 可能具有其他配体和功能。在这里，我们确定肌抑制肽 (MIP) 为 SPR 的第二个配体家族，该家族在广泛的无脊椎动物物种中保守。MIP 是果蝇、伊蚊和海兔 SPR 的体外强激动剂，但不能在体内触发交配后的反应。与 SP 不同，MIP 不是在雄性生殖器官中产生的，并且不是果蝇雌性交配后行为所必需的。我们得出结论，MIP 是 SPR 的进化保守配体，可能介导除调节雌性生殖行为以外的功能。
