The Drosophila lingerer protein cooperates with Orb2 in long-term memory formation

Abstract

Recently mated Drosophila females were shown to be reluctant to copulate and to exhibit rejecting behavior when courted by a male. Males that experience mate refusal by a mated female subsequently attenuate their courtship effort toward not only mated females but also virgin females. This courtship suppression persists for more than a day, and thus represents long-term memory. The courtship long-term memory has been shown to be impaired in heterozygotes as well as homozygotes of mutants in orb2, a locus encoding a set of CPEB RNA-binding proteins. We show that the impaired courtship long-term memory in orb2-mutant heterozygotes is restored by reducing the activity of lig, another putative RNA-binding protein gene, yet on its own the loss-of-function lig mutation is without effect. We further show that Lig forms a complex with Orb2. We infer that a reduction in the Lig levels compensates the Orb2 deficiency by mitigating the negative feedback for Orb2 expression and thereby alleviating defects in long-term memory.

Keywords:

• Courtship
• fruit fly
• memory mutants
• protein–protein interaction
• RNA-binding proteins

Acknowledgements

We thank A. Costa, C. Pazman, and the Bloomington Drosophila stock center for fly strains, S. Nomoto, G. Toba, K. Sunouchi, and N. Hamada-Kawaguchi for technical guidance, and M. Suyama for secretarial assistance.

Declaration of interest

The authors report no declarations of interest. The authors alone are responsible for the content and writing of the paper.

This work was supported by Grant-in-Aids for Scientific Research (Nos. 1802012, 23220007, and 24113502) from MEXT to D.Y.