Diatom centromeres suggest a mechanism for nuclear DNA acquisition

TitleDiatom centromeres suggest a mechanism for nuclear DNA acquisition
Publication TypeJournal Article
Year of Publication2017
AuthorsDiner RE, Noddings CM, Lian NC, Kang AK, McQuaid JB, Jablanovic J, Espinoza JL, Nguyen NA, Anzelmatti MA, Jansson J, Bielinski VA, Karas BJ, Dupont CL, Allen AE, Weyman PD
JournalProceedings of the National Academy of Sciences
Volume114
PaginationE6015-E6024
Date Published2017/07
Abstract

Centromeres are essential for cell division and growth in all eukaryotes, and knowledge of their sequence and structure guides the development of artificial chromosomes for functional cellular biology studies. Centromeric proteins are conserved among eukaryotes; however, centromeric DNA sequences are highly variable. We combined forward and reverse genetic approaches with chromatin immunoprecipitation to identify centromeres of the model diatom Phaeodactylum tricornutum. We observed 25 unique centromere sequences typically occurring once per chromosome, a finding that helps to resolve nuclear genome organization and indicates monocentric regional centromeres. Diatom centromere sequences contain low-GC content regions but lack repeats or other conserved sequence features. Native and foreign sequences with similar GC content to P. tricornutum centromeres can maintain episomes and recruit the diatom centromeric histone protein CENH3, suggesting nonnative sequences can also function as diatom centromeres. Thus, simple sequence requirements may enable DNA from foreign sources to persist in the nucleus as extrachromosomal episomes, revealing a potential mechanism for organellar and foreign DNA acquisition.

DOI10.1073/pnas.1700764114
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