Feed-Forward Loops in Eukaryotic Transcription Regulation

Abstract

Cellular characteristics are determined by molecular interactions. These interactions are complex, forming multi-layered networks that influence each other. One way to analyze these networks is by analyzing their constituent motifs. There have been several transcription regulatory motifs thought to have been selected by evolution that confers specific traits to the cell, one example being the feed forward loop (FFL) motif. It is a motif formed by three distinct nodes consisting of two regulators and one target. Depending on the type of interaction between the nodes, the motif enables the target node to have distinct dynamics advantageous to the cell as a whole, making them interesting study subjects. These motifs were initially studied in simple unicellular organisms. Comprehensive motif studies on more complex organisms have been hampered by the lack of important data sets, notably the gene expression data and transcription factor binding data. FFLs have nevertheless been described in several small-scale studies in more complex eukaryotes. This thesis presents an overview of these small-scale studies by discussing their proposed FFL motifs and their relation to the initial proposed FFL motif in simpler organisms.