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Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs

The nuclear pore complex (NPC) is a large macromolecular assembly situated within the pores of the nuclear envelope. Through interactions between its subcomplexes and import proteins, the NPC mediates the transport of molecules into and out of the nucleus and facilitates dynamic chromatin regulation...

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Autores principales: Irwin, Nicholas A T, Keeling, Patrick J
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411479/
https://www.ncbi.nlm.nih.gov/pubmed/30715330
http://dx.doi.org/10.1093/gbe/evz029
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author Irwin, Nicholas A T
Keeling, Patrick J
author_facet Irwin, Nicholas A T
Keeling, Patrick J
author_sort Irwin, Nicholas A T
collection PubMed
description The nuclear pore complex (NPC) is a large macromolecular assembly situated within the pores of the nuclear envelope. Through interactions between its subcomplexes and import proteins, the NPC mediates the transport of molecules into and out of the nucleus and facilitates dynamic chromatin regulation and gene expression. Accordingly, the NPC constitutes a highly integrated nuclear component that is ubiquitous and conserved among eukaryotes. Potential exceptions to this are nucleomorphs: Highly reduced, relict nuclei that were derived from green and red algae following their endosymbiotic integration into two lineages, the chlorarachniophytes and the cryptophyceans. A previous investigation failed to identify NPC genes in nucleomorph genomes suggesting that these genes have either been relocated to the host nucleus or lost. Here, we sought to investigate the composition of the NPC in nucleomorphs by using genomic and transcriptomic data to identify and phylogenetically classify NPC proteins in nucleomorph-containing algae. Although we found NPC proteins in all examined lineages, most of those found in chlorarachniophytes and cryptophyceans were single copy, host-related proteins that lacked signal peptides. Two exceptions were Nup98 and Rae1, which had clear nucleomorph-derived homologs. However, these proteins alone are likely insufficient to structure a canonical NPC and previous reports revealed that Nup98 and Rae1 have other nuclear functions. Ultimately, these data indicate that nucleomorphs represent eukaryotic nuclei without a canonical NPC, raising fundamental questions about their structure and function.
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spelling pubmed-64114792019-03-15 Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs Irwin, Nicholas A T Keeling, Patrick J Genome Biol Evol Research Article The nuclear pore complex (NPC) is a large macromolecular assembly situated within the pores of the nuclear envelope. Through interactions between its subcomplexes and import proteins, the NPC mediates the transport of molecules into and out of the nucleus and facilitates dynamic chromatin regulation and gene expression. Accordingly, the NPC constitutes a highly integrated nuclear component that is ubiquitous and conserved among eukaryotes. Potential exceptions to this are nucleomorphs: Highly reduced, relict nuclei that were derived from green and red algae following their endosymbiotic integration into two lineages, the chlorarachniophytes and the cryptophyceans. A previous investigation failed to identify NPC genes in nucleomorph genomes suggesting that these genes have either been relocated to the host nucleus or lost. Here, we sought to investigate the composition of the NPC in nucleomorphs by using genomic and transcriptomic data to identify and phylogenetically classify NPC proteins in nucleomorph-containing algae. Although we found NPC proteins in all examined lineages, most of those found in chlorarachniophytes and cryptophyceans were single copy, host-related proteins that lacked signal peptides. Two exceptions were Nup98 and Rae1, which had clear nucleomorph-derived homologs. However, these proteins alone are likely insufficient to structure a canonical NPC and previous reports revealed that Nup98 and Rae1 have other nuclear functions. Ultimately, these data indicate that nucleomorphs represent eukaryotic nuclei without a canonical NPC, raising fundamental questions about their structure and function. Oxford University Press 2019-02-04 /pmc/articles/PMC6411479/ /pubmed/30715330 http://dx.doi.org/10.1093/gbe/evz029 Text en © The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Irwin, Nicholas A T
Keeling, Patrick J
Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs
title Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs
title_full Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs
title_fullStr Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs
title_full_unstemmed Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs
title_short Extensive Reduction of the Nuclear Pore Complex in Nucleomorphs
title_sort extensive reduction of the nuclear pore complex in nucleomorphs
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6411479/
https://www.ncbi.nlm.nih.gov/pubmed/30715330
http://dx.doi.org/10.1093/gbe/evz029
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