MECHANISMS OF DEVELOPMENTAL PLASTICITY

While developmental events are generally tightly controlled during embryogenesis, a certain level of flexibility exists. This so-called developmental plasticity allows an organism to adjust in response to environmental factors experienced during early stages of development or even to the parental environment. For example, it has been shown that the metabolic state of the parents at conception can influence embryo development and subsequently affect the characteristics of their offspring.

The mechanisms by which the next generation retains a memory of the parental environment, however, are not yet clear. The aim of this award is to gain an understanding of how maternal metabolic state - excess, normal, and reduced long term calorie intake - alters the development and traits of their children. In this study, the researchers use fruit flies as a model.

Fruit flies are ideal for this research because, once the mother lays the eggs, they develop on their own without any further input from the mother, unlike in mammals. This allows the researchers to directly address the impact of the maternal environment before conception on embryo development. They will utilize a novel methodology to determine how embryonic metabolism and gene expression changes in response to maternal metabolic state and perform experiments to understand how these molecular changes influence developmental outcomes to trigger life-long changes.

Additionally, a new hands-on teaching module for a K-12 afterschool program will be developed and turned into digital lessons to be distributed to educators across the country in collaboration with the Van Andel Education Institute.

How parental metabolic states translate into distinct developmental trajectories and adult phenotypes remains unclear. This study will investigate the matrilineal effects of metabolic state on offspring development. The objectives are to determine the impact of maternal metabolic state on metabolic and transcriptional processes and epigenomic profiles in offspring embryos and link the maternal intergenerational signal to offspring reprogramming events and phenotypes.

Technical limitations, due to the fast progression of development and small amount of material available during the early embryonic time window, have been barriers to studying developmental plasticity. This group recently reported a new single embryo RNA-sequencing methodology that overcomes these limitations. Using this methodology they will generate a time-resolved, integrated transcriptomic and metabolic dataset of reprogramming events, triggered by maternal metabolic state, during early (10 min–3h) Drosophila embryogenesis.

They will determine how these metabolite and transcriptome changes translate into differences in chromatin associated histone marks by assessing their genome wide distribution at different developmental timepoints. To test if substrate availability and/or enzymes involved in histone modifications are a driver of the intergenerational phenotype, two different approaches will be employed 1) shRNA-knockdown (KD) experiments in the oocyte and zygote and 2) dietary supplementation.

The combination of newly developed tools with traditional epigenomic and shRNA knock-down analysis will facilitate the identification of the earliest reprogramming signatures and allow the tracking of those signatures through to specific developmental programs and adult phenotypes. The Broader Impact activities include development of an educational module on epigenetics and the impact of external forces on embryonic development for K-12 students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.