Sequence, chromatin and evolution of satellite dna

• Type of Material: Article
• Authors: Jitendra Thakur, Emory University; Jenika Packiaraj, Emory University; Steven Henikoff, Fred Hutchinson Cancer Research Center
• Language: English
• Date: 2021-05-01
• Publisher: MDPI
• Publication Version: Final Published Version
• Copyright Statement: © 2021 by the authors.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.3390/ijms22094309
• Title of Journal or Parent Work: International Journal of Molecular Sciences
• Volume: 22
• Issue: 9
• Grant/Funding Information: J.T. is supported by the Department of Biology, Emory University start-up funds. S.H. is an Investigator of the Howard Hughes Medical Institute.
• Keywords: Humans; CENP-A; heterochromatin; telomeres; centromeres; DNA, Satellite; Species Specificity; Animals; H3K9me3; repetitive DNA; Centromere; non-B-form DNA; Chromatin; Evolution, Molecular
• Research Categories: Health Sciences, Oncology; Biology, General

Abstract

Satellite DNA consists of abundant tandem repeats that play important roles in cellular processes, including chromosome segregation, genome organization and chromosome end protec-tion. Most satellite DNA repeat units are either of nucleosomal length or 5–10 bp long and occupy centromeric, pericentromeric or telomeric regions. Due to high repetitiveness, satellite DNA sequences have largely been absent from genome assemblies. Although few conserved satellite-specific sequence motifs have been identified, DNA curvature, dyad symmetries and inverted repeats are features of various satellite DNAs in several organisms. Satellite DNA sequences are either embed-ded in highly compact gene-poor heterochromatin or specialized chromatin that is distinct from euchromatin. Nevertheless, some satellite DNAs are transcribed into non-coding RNAs that may play important roles in satellite DNA function. Intriguingly, satellite DNAs are among the most rapidly evolving genomic elements, such that a large fraction is species-specific in most organisms. Here we describe the different classes of satellite DNA sequences, their satellite-specific chromatin features, and how these features may contribute to satellite DNA biology and evolution. We also discuss how the evolution of functional satellite DNA classes may contribute to speciation in plants and animals.