Investigating Imprinted Genes in Adipose Tissue

Abstract

The obesity epidemic has spotlighted the importance of understanding the growth and development of adipose tissue. The biology of the tissue is poorly understood, and current research suggests that the imprinted gene network may play a role in regulating their growth and development. We propose that imprinted genes act in a regulatory network to control adipose development. This study will i) describe expression of a perilipin (a lipid droplet marker for adipocytes), ii) describe the expression of DLK1 and whether the deletion of DLK1 will affect early adipose mass, iii) determine the expression of other members of the imprinted gene network (Zac1, Cdkn1c/P57KIP2 and Men1). Immunohistochemistry on the whole embryos at e15.5 and e18.5 was used to determine gene expression and stereology to assess adipose mass. We found that the expression of perilipin to be restricted to early adipocytes, with expression in BAT and WAT depots. Similar expression is seen for DLK1, and by knocking out the expression, the volume of adipose tissue was significantly reduced compared to wild type. The expression of other members of the imprinted gene network (Zac1, Cdkn1c/P57KIP2 and Men1) was also noted for BAT at either e15.5 or e18.5, indicating their expression can play a role in adipose development. They all show various expression at a number of different tissues related to their function, which is out of the scope of this study. To conclude, we detect the expression of imprinted genes developing adipose tissue and the deletion of DLK1 significantly reduces adipose mass.