How specific brain cells in fruit flies control daily activity and emergence timing by removing them or increasing a key clock protein

Genetic ablation of ventral lateral neurons in Drosophila results in the loss of robust 24-hour activity rhythms.

• Ablation of LNvs leads to a phase advance in light-dark conditions and a weak short-period rhythm in constant darkness.
• Disco1 mutants also display reduced numbers of lateral neurons that fail to express the PER protein, mirroring LNv-ablated behavioral phenotypes.
• Weak short-period rhythms observed in LNv-ablated and disco1 flies may originate from dorsal neurons that do not express PDF.
• Overexpression of the per gene in LNs disrupts both activity and eclosion rhythms, indicating the importance of PER cycling in these neurons.
• Flies with PER overexpression in LNs do not exhibit weak short-period rhythms, highlighting the dominant role of LNs in regulating behavioral rhythms.
• Expression of a synaptic toxin in the LNvs does not affect activity rhythms, suggesting that PDF-expressing neurons may not rely on specific synaptic transmission mechanisms.

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