Dissection of the Regulatory Elements of the Complex Expression Pattern of Puckered, a Dual-Specificity JNK Phosphatase

Abstract

For developmental processes, we know most of the gene networks controlling specific cell responses. We still have to determine how these networks cooperate and how signals become integrated. The JNK pathway is one of the key elements modulating cellular responses during development. Yet, we still know little about how the core components of the pathway interact with additional regulators or how this network modulates cellular responses in the whole organism in homeostasis or during tissue morphogenesis. We have performed a promoter analysis, searching for potential regulatory sequences of puckered (puc) and identified different specific enhancers directing gene expression in different tissues and at different developmental times. Remarkably, some of these domains respond to the JNK activity, but not all. Altogether, these analyses show that puc expression regulation is very complex and that JNK activities participate in non-previously known processes during the development of Drosophila.

JNK signaling and integrins cooperate to maintain cell adhesion during epithelial fusion in Drosophila

“…A plausible explanation is that puc expression in these dying cells or in cells losing cell-cell contacts could depend on the activity of non-canonical AP1 enhancers. Indeed, we recently identified a plethora of enhancers on puc acting in different tissues and developmental times ( Llense and Martin-Blanco, 2008 ; Karkali and Martin-Blanco, 2021 ). Alternatively, the elimination, in the absence of an upstream input, of the negative feedback implemented by puc via dephosphorylation of JNK could, depending on the stability and/or the abundance of the phosphorylated form of the JNK, result in the net activation of the pathway.…”