Tracking enhancers during development
6 Feb 2012 by Evoluted New Media
Genetic sequences known as enhancers act like remote controls switching genes on and off and scientists in Germany can see and predict exactly when each remote control is activated in a real embryo.
Different genes are switched on in different cells during embryo development, forming muscles, neurons and other bodily parts. Inside each cell, enhancers are switching these genes on and off and researchers from the European Molecular Biology Laboratory (EMBL) have assessed the relationship between the spatiotemporal activity of these enhancers and chromatin modifications – chemical tags that promote or hinder gene expression.
Scientists in the laboratory of Eileen Furlong used a new approach to obtain cell type-specific information on chromatin state and RNA polymerase II within multicellular Drosophila melanogaster embryos.
“Our new method provides cell-type specific information on the activity status of an enhancer and of a gene, within a developing multicellular embryo,” said Furlong.
They found that specific combinations of chromatin modifications are placed at and removed from enhancers at precise times during development, switching the remote controls off or on.
The scientists – including Stefan Bonn, Robert Zinzen and Charles Giradot – compared active and inactive enhancers in the mesoderm of the fruit fly at a particular time during development. They noted what chromatin modifications each enhancer had, and trained a computer model to accurately predict if the enhancer is active or not, based solely on what chromatin mark it bears.
Their paper – published in Nature Genetics – states: “This cell type–specific view identifies dynamic enhancer usage, an essential step in deciphering developmental networks.”
The researchers plan to use this method to study the interactions between the activity status on and enhancer and the presence of key switches or transcription factors at different stages of embryonic development and in different tissue types. They hope to develop a complete picture of how a single cell grows into a complex organism.
