The MicroRNA miR‐8 is a positive regulator of pigmentation and eclosion in Drosophila

Abstract

Background: MicroRNAs (miRNAs) are short, non‐coding RNAs that post‐transcriptionally silence gene expression by binding to target mRNAs. Previous studies have identified the miRNA miR‐8 as a pleiotropic regulator of Drosophila development, controlling body size and neuronal survival by targeting multiple mRNAs. In this study we demonstrate that miR‐8 is also required for proper spatial patterning of pigment on the adult abdominal cuticle in females but not males. Results: Female adult flies lacking miR‐8 exhibit decreased pigmentation of the dorsal abdomen, with a pattern of pigmentation similar to wild type flies grown at higher temperatures. This pigmentation defect in miR‐8 mutants is independent of the previously reported body size defect, and miR‐8 acts directly in the developing cuticle to regulate pigmentation patterning. The decrease in pigmentation in miR‐8 mutants was more pronounced in flies grown at higher temperatures. We also found that loss of miR‐8 dramatically affected the ability to eclose at higher temperatures. Conclusion: Loss of miR‐8 increased the sensitivity of Drosophila to higher temperatures for both pigmentation patterning and the ability to eclose. Together, these data suggest that miR‐8 acts as a buffer to stabilize gene expression patterns in the midst of environmental variation. Developmental Dynamics 241:161–168, 2012. © 2011 Wiley Periodicals, Inc. Key findings: miR‐8 is required for proper spatial patterning of pigment on adult female abdomens. The pigmentation patterning defect in miR‐8 mutants is independent of the small body size defect. Loss of miR‐8 in the developing cuticle results in cell‐autonomous loss of pigmentation. MiR‐8 is expressed in the epidermis underlying the dorsal abdominal cuticle. Loss of miR‐8 sensitizes flies to effects of higher growth temperatures on eclosion success and pigmentation patterning.