A widely employed germ cell marker is an ancient disordered protein with reproductive functions in diverse eukaryotes
The advent of sexual reproduction and the evolution of a dedicated germline in multicellular organisms are critical landmarks in eukaryotic evolution. We report an ancient family of GCNA (germ cell nuclear antigen) proteins that arose in the earliest eukaryotes, and feature a rapidly evolving intrinsically disordered region (IDR). Phylogenetic analysis reveals that GCNA proteins emerged before the major eukaryotic lineages diverged; GCNA predates the origin of a dedicated germline by a billion years. Gcna gene expression is enriched in reproductive cells across eukarya - either just prior to or during meiosis in single-celled eukaryotes, and in stem cells and germ cells of diverse multicellular animals. Studies of Gcna-mutant C. elegans and mice indicate that GCNA has functioned in reproduction for at least 600 million years. Homology to IDR-containing proteins implicated in DNA damage repair suggests that GCNA proteins may protect the genomic integrity of cells carrying a heritable genome.
Article and author information
Howard Hughes Medical Institute
- Michelle A Carmell
- Gregoriy A Dokshin
- Helen Skaletsky
- Yueh-Chiang Hu
- Kyomi J Igarashi
- Daniel W Bellott
- Peter W Reddien
- Craig C Mello
Life Sciences Research Foundation
- Michelle A Carmell
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All mouse studies were performed using a protocol approved by the Committee on Animal Care at the Massachusetts Institute of Technology (Protocol number: 0714-074-17).
- Yukiko M Yamashita, University of Michigan, United States
- Received: July 27, 2016
- Accepted: October 5, 2016
- Accepted Manuscript published: October 8, 2016 (version 1)
- Accepted Manuscript updated: October 21, 2016 (version 2)
- Version of Record published: November 7, 2016 (version 3)
© 2016, Carmell et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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