Chip Is Required for Posteclosion Behavior inDrosophila

Abstract

Neurons acquire their molecular, neurochemical, and connectional features during development as a result of complex regulatory mechanisms. Here, we show that a ubiquitous, multifunctional protein cofactor, Chip, plays a critical role in a set of neurons in Drosophila that control the well described posteclosion behavior. Newly eclosed flies normally expand their wings and display tanning and hardening of their cuticle. Using multiple approaches to interfere with Chip function, we find that these processes do not occur without normal activity of this protein. Furthermore, we identified the nature of the deficit to be an absence of Bursicon in the hemolymph of newly eclosed flies, whereas the responsivity to Bursicon in these flies remains normal. Chip interacts with transcription factors of the LIM-HD (LIM-homeodomain) family, and we identified one member, dIslet, as a potential partner of Chip in this process. Our findings provide the first evidence of transcriptional mechanisms involved in the development of the neuronal circuit that regulates posteclosion behavior in Drosophila.

Modulation of light-driven arousal by LIM-homeodomain transcription factor Apterous in large PDF-positive lateral neurons of the Drosophila brain

“…The transcriptional activity of Ap/Chi is expected to be inhibited by the induction of these truncated forms because they can interfere with the formation of the functional Ap/Chi tetramer. Actually, expression of Chi ΔLID or Chi ΔDD induces the dominant negative effects in wing development or posteclosion behavior requiring Chi functions1231. As was observed in Pdf -GAL4/UAS- Chi RNAi flies, the targeted expression of Chi ΔLID in PDF neurons reduced sleep amount during the day and increased waking time in the morning and evening (Fig.…”

The pronotum LIM-HD gene tailup is both a positive and a negative regulator of the proneural genes achaete and scute of Drosophila

“…This suggests that activation of this enhancer probably requires the postulated 2Tup-2Chip-2Ssdp hexameric complex (Fig. 5A), similarly to other LIM-HD factors that regulate transcription (Ferná ndez-Fú nez et al, 1998;Milá n and Cohen, 1999;Rincó n-Limas et al, 2000;van Meyel et al, 2000van Meyel et al, , 2003, and Tup itself in other contexts (de Navascué s and Modolell, 2007;Hari et al, 2008). Pnr, a direct activator of the DC enhancer, most likely does not mediate the Tup effect ( Fig.…”

“…The cofactor Chip seems to be central for Tup functions in all contexts examined so far, even though the interaction can be either cooperative (de Navascué s and Modolell, 2007;Hari et al, 2008;Thor and Thomas, 1997) or antagonistic (Biryukova and Heitzler, 2005). In the DC region both factors cooperate in promoting bristle development.…”

Chip physically interacts with Notch and their stoichiometry is critical for Notch function in wing development and cell proliferation in Drosophila

“…and Chip form a functional complex, which is a tetramer formed by two Ap molecules bridged by two Chip molecules, was established [25,27,28,30]. Chip has also been reported for regulating axon guidance [31], posteclosion behavior [32], and establishing the boundary of the eye field [33] in Drosophila.…”