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Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea

Halophilic archaea experience high levels of ultraviolet (UV) light in their environments and demonstrate resistance to UV irradiation. DNA repair systems and carotenoids provide UV protection but do not account for the high resistance observed. Herein, we consider genomic signatures as an additiona...

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Autores principales: Jones, Daniel L., Baxter, Bonnie K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5041013/
https://www.ncbi.nlm.nih.gov/pubmed/27598206
http://dx.doi.org/10.3390/life6030037
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author Jones, Daniel L.
Baxter, Bonnie K.
author_facet Jones, Daniel L.
Baxter, Bonnie K.
author_sort Jones, Daniel L.
collection PubMed
description Halophilic archaea experience high levels of ultraviolet (UV) light in their environments and demonstrate resistance to UV irradiation. DNA repair systems and carotenoids provide UV protection but do not account for the high resistance observed. Herein, we consider genomic signatures as an additional photoprotective strategy. The predominant forms of UV-induced DNA damage are cyclobutane pyrimidine dimers, most notoriously thymine dimers (T^Ts), which form at adjacent Ts. We tested whether the high G + C content seen in halophilic archaea serves a photoprotective function through limiting T nucleotides, and thus T^T lesions. However, this speculation overlooks the other bipyrimidine sequences, all of which capable of forming photolesions to varying degrees. Therefore, we designed a program to determine the frequencies of the four bipyrimidine pairs (5’ to 3’: TT, TC, CT, and CC) within genomes of halophilic archaea and four other randomized sample groups for comparison. The outputs for each sampled genome were weighted by the intrinsic photoreactivities of each dinucleotide pair. Statistical methods were employed to investigate intergroup differences. Our findings indicate that the UV-resistance seen in halophilic archaea can be attributed in part to a genomic strategy: high G + C content and the resulting bipyrimidine signature reduces the genomic photoreactivity.
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spelling pubmed-50410132016-10-05 Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea Jones, Daniel L. Baxter, Bonnie K. Life (Basel) Article Halophilic archaea experience high levels of ultraviolet (UV) light in their environments and demonstrate resistance to UV irradiation. DNA repair systems and carotenoids provide UV protection but do not account for the high resistance observed. Herein, we consider genomic signatures as an additional photoprotective strategy. The predominant forms of UV-induced DNA damage are cyclobutane pyrimidine dimers, most notoriously thymine dimers (T^Ts), which form at adjacent Ts. We tested whether the high G + C content seen in halophilic archaea serves a photoprotective function through limiting T nucleotides, and thus T^T lesions. However, this speculation overlooks the other bipyrimidine sequences, all of which capable of forming photolesions to varying degrees. Therefore, we designed a program to determine the frequencies of the four bipyrimidine pairs (5’ to 3’: TT, TC, CT, and CC) within genomes of halophilic archaea and four other randomized sample groups for comparison. The outputs for each sampled genome were weighted by the intrinsic photoreactivities of each dinucleotide pair. Statistical methods were employed to investigate intergroup differences. Our findings indicate that the UV-resistance seen in halophilic archaea can be attributed in part to a genomic strategy: high G + C content and the resulting bipyrimidine signature reduces the genomic photoreactivity. MDPI 2016-09-02 /pmc/articles/PMC5041013/ /pubmed/27598206 http://dx.doi.org/10.3390/life6030037 Text en © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jones, Daniel L.
Baxter, Bonnie K.
Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea
title Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea
title_full Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea
title_fullStr Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea
title_full_unstemmed Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea
title_short Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea
title_sort bipyrimidine signatures as a photoprotective genome strategy in g + c-rich halophilic archaea
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5041013/
https://www.ncbi.nlm.nih.gov/pubmed/27598206
http://dx.doi.org/10.3390/life6030037
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