Gradual release of sperm bound sex-peptide controls female postmating behavior in Drosophila
Gradual release of sperm bound sex-peptide controls female postmating behavior in Drosophila
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DOI：
10.1016/j.cub.2005.01.034
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发表时间：
2005-02-08
期刊：
影响因子：
9.2
通讯作者：
Kubli, E
中科院分区：
文献类型：
--
作者：
Peng, J;Chen, S;Kubli, E
背景资料：在许多雌性昆虫中，在精液中转移的肽诱导交配后反应（PMR），例如产卵的急剧增加和感受性（准备交配）的降低。在果蝇中，性肽（SP）elermines短期和长期的PMR，但只有后者在存在存储的精子（精子效应）。结果：在这里，我们阐明SP和精子之间的相互作用免疫荧光显微镜。以转基因雄性为材料，研究了SP修饰对雌性体内PMR的影响。我们报告，SP结合精子与其N-末端。在雌性中，已知对诱导PMR至关重要的SP的C-末端部分通过在胰蛋白酶切割位点处的切割从储存的精子中逐渐释放，从而延长PMR。通过分析含有编码修饰SP的转基因的雄性引起的PMR证实了这些发现。缺少N末端的SP不能与精子结合，缺少胰蛋白酶切割位点的SP能与精子永久结合。因此，除了遗传信息的载体，精子也是SP的载体。与精子结合可以保护肽免受血淋巴中蛋白酶的降解，从而延长其半衰期。较长的精子尾部可以转移更多的SP，从而增加雄性的生殖适应度。我们认为，这可以解释在某些果蝇物种的精子尾巴过长。
Background: In many female insects, peptides transferred in the seminal fluid induce postmating responses (PMR), such as a drastic increase of egg laying and reduction of receptivity (readiness to mate). In Drosophila melanogaster, sex-peptide (SP) elicits short- and long-term PMR, but only the latter in the presence of stored sperm (sperm effect).Results: Here, we elucidate the interaction between SP and sperm by immunofluorescence microscopy. Transgenic males were used to study the effects of SP modification on the PMR of females in vivo. We report that SP binds to sperm with its N-terminal end. In females, the C-terminal part of SP known to be essential to induce the PMR is gradually released from stored sperm by cleavage at a trypsin cleavage site, thus prolonging the PMR. These findings are confirmed by analyzing the PMR elicited by males containing transgenes encoding modified SPs. SP lacking the N-terminal end cannot bind, and SP without the trypsin cleavage site binds permanently to sperm.Conclusion: By binding to sperm tails, SP prolongs the PMR. Thus, besides a carrier for genetic information, sperm is also the carrier for SP. Binding to sperm may protect the peptide from degradation by proteases in the hemolymph and,,thus, prolong its half-life. Longer sperm tails may transfer more SP and thus increase the reproductive fitness of the male. We suggest that this could explain the excessive length of sperm tails in some Drosophila species.