The insulin/Insulin-Like Growth Factor (IGF) pathway is essential for linking nutritional status to growth and metabolism. MicroRNAs (miRNAs) are short RNAs that are players in the regulation of this process. The miRNA miR-7 shows highly conserved expression in insulin-producing cells across the animal kingdom. However, its conserved functions in regulation of insulin-like peptides (ILPs) remain unknown. Using Drosophila as a model, I demonstrate that miR-7 limits ILP availability by inhibiting its production and secretion. Increasing miR-7 alters body growth and metabolism in an ILP-dependent manner, elevating circulating sugars and total body triglycerides, while decreasing animal growth. These effects are not due to direct targeting of ILP mRNA, but instead arise through alternate targets that affect the function of ILP-producing cells. The Drosophila F-actin capping protein alpha, CPA, is a direct target of miR-7, and knockdown of CPA in IPCs phenocopies the effects of miR-7 on ILP secretion. This regulation of CPA is conserved in mammals, with the mouse ortholog Capza1 also targeted by miR-7 in β-islet cells. This result supports a conserved role for miR-7 regulation of an actin capping protein in insulin regulation, and highlights a conserved mechanism of action for an evolutionarily ancient microRNA.

Creator

• Agbu, Pamela

DOI

• https://doi.org/10.21985/n2-kcy1-mx29

Subject

• Molecular biology
• Endocrinology

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:15272
• etdadmin_upload_764541

Keyword

• MicroRNA
• Insulin
• Drosophila

Date created

• 2020-01-01

Resource type

• Dissertation

Rights statement

• In Copyright