Download or read book Evolution of 3D Chromatin Architecture written by Liene Astica and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Englische Version: The three-dimensional organization of animal genomes, known as topologically associating domains (TADs), is crucial for controlling gene activity. TADs are regions with increased genetic interactions, separated by zones with fewer contacts. In vertebrates, the formation of TADs involves a dynamic process called loop extrusion, where cohesin and CTCFs bind to the chromatin. This process creates chromatin loops, with cohesin complexes pausing when they encounter CTCF molecules in a specific orientation. However, although CTCF is highly conserved among bilaterian species, its vital role in organizing genomes spatially has not been observed in invertebrates like flies. This study investigates the chromatin structure in Ciona robusta, a chordate species situated evolutionarily between well-studied organisms like mice and fruit flies. A unique approach was developed to explore the evolution of CTCF as a mediator of three-dimensional chromatin organization. By swapping CTCF orthologs from representative species across the bilaterian group, the research examined their impact on viability, traits, gene expression, genome architecture, and binding patterns across the genome. The findings indicate that Ciona robusta, a non-vertebrate chordate, lacks typical TAD structures, even in the presence of CTCF. However, although the Ciona ortholog cannot create TADs in mouse embryonic stem cells, it can act as a transcription factor, restoring the expression of specific genes and viability in cases of complete CTCF loss. This suggests that CTCF serves a conserved role as a transcription regulator, beyond its recognized role as a structural component in some species. Furthermore, when the mouse ortholog of CTCF was introduced into the fruit fly genome, it failed to induce the formation of chromatin loops, suggesting that the vertebrate version of CTCF alone is insufficient for effective loop extrusion. [...].