Kai Chen

Zeitlinger Laboratory

Chromatin organization during Drosophila early embryogenesis

The development of multi-cellular animals begins with a fertilized egg, which divides and differentiates into different cell types. These cell types form different organs and finally the whole organism without changing their genetic information – the DNA sequence. To acquire different functional properties, different cell types switch distinct genes on or off through the binding of specific transcriptional regulators and RNA Polymerase II. Another layer of regulation is the way DNA is packaged into chromatin, which determines the accessibility of DNA to transcriptional regulators in a tissue-specific manner. Recent progress in high-throughput sequencing allows the precise mapping of transcriptional regulators and chromatin accessibility, which presents an opportunity to study the interplay between transcriptional regulators and chromatin on a genomic level.

In particular, very little is known about how chromatin is organized during early embryogenesis, when transcription has not yet begun, and whether the initial chromatin organization helps determine which genes are transcribed first. To address this question, I am using the Drosophila embryo as model system since large amounts can be produced and the early stages of its development have been well studied by traditional methods. Understanding how different chromatin structures are formed and may regulate transcription at a genome-wide is a fundamental problem and could be applicable to understand gene regulation in humans.