Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
Department of Neurological Sciences, University of Vermont, Burlington, VT, USA.
Nature. 2020 Mar;579(7797):101-105. doi: 10.1038/s41586-020-2055-9. Epub 2020 Feb 26.
Mating and egg laying are tightly cooordinated events in the reproductive life of all oviparous females. Oviposition is typically rare in virgin females but is initiated after copulation. Here we identify the neural circuitry that links egg laying to mating status in Drosophila melanogaster. Activation of female-specific oviposition descending neurons (oviDNs) is necessary and sufficient for egg laying, and is equally potent in virgin and mated females. After mating, sex peptide-a protein from the male seminal fluid-triggers many behavioural and physiological changes in the female, including the onset of egg laying. Sex peptide is detected by sensory neurons in the uterus, and silences these neurons and their postsynaptic ascending neurons in the abdominal ganglion. We show that these abdominal ganglion neurons directly activate the female-specific pC1 neurons. GABAergic (γ-aminobutyric-acid-releasing) oviposition inhibitory neurons (oviINs) mediate feed-forward inhibition from pC1 neurons to both oviDNs and their major excitatory input, the oviposition excitatory neurons (oviENs). By attenuating the abdominal ganglion inputs to pC1 neurons and oviINs, sex peptide disinhibits oviDNs to enable egg laying after mating. This circuitry thus coordinates the two key events in female reproduction: mating and egg laying.
交配和产卵是所有卵生雌性动物生殖生活中紧密协调的事件。初产雌蝇通常很少产卵，但交配后会开始产卵。在这里，我们确定了将产卵与交配状态联系起来的果蝇神经回路。激活雌性特异性产卵下行神经元（oviDN）对于产卵是必要且充分的，在处女蝇和交配后的雌蝇中同样有效。交配后，来自雄性精液的性肽-一种蛋白质-会引发雌性的许多行为和生理变化，包括开始产卵。性肽被子宫中的感觉神经元检测到，并使这些神经元及其在腹部神经节中的突触后上行神经元沉默。我们表明，这些腹部神经节神经元直接激活雌性特异性 pC1 神经元。GABA 能（γ-氨基丁酸释放）产卵抑制神经元（oviIN）介导来自 pC1 神经元对 oviDN 和其主要兴奋性输入，即产卵兴奋性神经元（oviEN）的前馈抑制。通过减弱腹部神经节对 pC1 神经元和 oviIN 的输入，性肽抑制 oviDN，从而在交配后能够产卵。因此，这个回路协调了雌性生殖的两个关键事件：交配和产卵。
