dorsal closure is a morphogenetic movement that involves flanking epidermal cells, assembling actomyosin cables, and migrating dorsally over the underlying amnioserosa to seal at the dorsal midline. Echinoid (Ed)-a cell adhesion molecule of adherens junctions (AJs)-participates in several developmental processes. The disappearance of Ed from the amnioserosa is required to define the epidermal leading edge for actomyosin cable assembly and coordinated cell migration. However, the mechanism by which Ed is cleared from amnioserosa is unknown. Here, we show that Ed is cleared in amnioserosa by both transcriptional and post-translational mechanisms. First, mRNA transcription was repressed in amnioserosa prior to the onset of dorsal closure. Second, the ubiquitin ligase Smurf downregulated pretranslated Ed by binding to the PPXY motif of Ed. During dorsal closure, Smurf colocalized with Ed at AJs, and Smurf overexpression prematurely degraded Ed in the amnioserosa. Conversely, Ed persisted in the amnioserosa of mutant embryos, which, in turn, affected actomyosin cable formation. Together, our results demonstrate that transcriptional repression of followed by Smurf-mediated downregulation of pretranslated Ed in amnioserosa regulates the establishment of a taut leading edge during dorsal closure.

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Farmers’ behaviors to deal with climate change can be divided into two categories: mitigation and adaptation. Mitigation behaviors can reduce the rate of climate change, while adaptation behaviors can reduce the vulnerability to climate change. In this study, we focused on the factors influencing farmers’ behavioral preferences and explored the differences in their behaviors in response to climate change in different types of regions. A structural equation model was constructed to describe the relationship between trust, risk perception, psychological distance and risk severity, and farmer behaviors. The results indicate that the factors affecting climate adaptation vary greatly in different regions. In agricultural areas, risk salience, psychological distance and mitigation behaviors had an important influence on farmer adaptation behavior, while risk perception only affects farmers’ mitigation behaviors. Trust can not only predict farmers’ adaptability, but also explain farmers’ choice of mitigation behaviors. For farmers in farming and pastoral areas, belief, risk severity level and trust have positive driving effects on both adaptation and mitigation behaviors. The findings provide suggestions for the development of public policy and risk management approaches to deal with climate change, which could encourage active behavior among farmers.

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