Drosophila insulin-like peptide 1 (DILP1) is transiently expressed during non-feeding stages and reproductive dormancy
Sci Rep. 2016-05-20; 6(1):
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Liu Y(1), Liao S(1), Veenstra JA(2), Nässel DR(1).
(1)Department of Zoology, Stockholm University, S-10691 Stockholm, Sweden.
(2)INCIA UMR 5287 CNRS, Université de Bordeaux, 33405 Talence Cedex, France.
The insulin/insulin-like growth factor signaling pathway is evolutionarily
conserved in animals, and is part of nutrient-sensing mechanisms that control
growth, metabolism, reproduction, stress responses, and lifespan. In Drosophila,
eight insulin-like peptides (DILP1-8) are known, six of which have been
investigated in some detail, whereas expression and functions of DILP1 and DILP4
remain enigmatic. Here we demonstrate that dilp1/DILP1 is transiently expressed
in brain insulin producing cells (IPCs) from early pupa until a few days of adult
life. However, in adult female flies where diapause is triggered by low
temperature and short days, within a time window 0-10h post-eclosion, the
dilp1/DILP1 expression remains high for at least 9 weeks. The dilp1 mRNA level is
increased in dilp2, 3, 5 and dilp6 mutant flies, indicating feedback regulation.
Furthermore, the DILP1 expression in IPCs is regulated by short neuropeptide F,
juvenile hormone and presence of larval adipocytes. Male dilp1 mutant flies
display increased lifespan and reduced starvation resistance, whereas in female
dilp1 mutants oviposition is reduced. Thus, DILP1 is expressed in non-feeding
stages and in diapausing flies, is under feedback regulation and appears to play
sex-specific functional roles.