Multi-Scale Organization of the <i>Drosophila melanogaster</i> Genome

• Main Authors: Samantha C. Peterson, Kaylah B. Samuelson, Stacey L. Hanlon
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Genes
• Subjects: <i>Drosophila</i>; topologically associating domain; insulator; pairing; transvection; B chromosome
• Online Access: https://www.mdpi.com/2073-4425/12/6/817

Interphase chromatin, despite its appearance, is a highly organized framework of loops and bends. Chromosomes are folded into topologically associating domains, or TADs, and each chromosome and its homolog occupy a distinct territory within the nucleus. In <i>Drosophila</i>, genome organization is exceptional because homologous chromosome pairing is in both germline and somatic tissues, which promote interhomolog interactions such as transvection that can affect gene expression in <i>trans</i>. In this review, we focus on what is known about genome organization in <i>Drosophila</i> and discuss it from TADs to territory. We start by examining intrachromosomal organization at the sub-chromosome level into TADs, followed by a comprehensive analysis of the known proteins that play a key role in TAD formation and boundary establishment. We then zoom out to examine interhomolog interactions such as pairing and transvection that are abundant in <i>Drosophila</i> but rare in other model systems. Finally, we discuss chromosome territories that form within the nucleus, resulting in a complete picture of the multi-scale organization of the <i>Drosophila</i> genome.