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Sequence permutations in the molecular evolution of DNA methyltransferases
BACKGROUND: DNA methyltransferases (MTases), unlike MTases acting on other substrates, exhibit sequence permutation. Based on the sequential order of the cofactor-binding subdomain, the catalytic subdomain, and the target recognition domain (TRD), several classes of permutants have been proposed. Th...
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BioMed Central
2002
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC102321/ https://www.ncbi.nlm.nih.gov/pubmed/11914127 http://dx.doi.org/10.1186/1471-2148-2-3 |
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author | Bujnicki, Janusz M |
author_facet | Bujnicki, Janusz M |
author_sort | Bujnicki, Janusz M |
collection | PubMed |
description | BACKGROUND: DNA methyltransferases (MTases), unlike MTases acting on other substrates, exhibit sequence permutation. Based on the sequential order of the cofactor-binding subdomain, the catalytic subdomain, and the target recognition domain (TRD), several classes of permutants have been proposed. The majority of known DNA MTases fall into the α, β, and γ classes. There is only one member of the ζ class known and no members of the δ and ε classes have been identified to date. Two mechanisms of permutation have been proposed: one involving gene duplication and in-frame fusion, and the other involving inter- and intragenic shuffling of gene segments. RESULTS: Two novel cases of sequence permutation in DNA MTases implicated in restriction-modification systems have been identified, which suggest that members of the δ and ζ classes (M.MwoI and M.TvoORF1413P, respectively) evolved from β-class MTases. This is the first identification of the δ-class MTase and the second known ζ-class MTase (the first ζ-class member among DNA:m(4)C and m(6)A-MTases). CONCLUSIONS: Fragmentation of a DNA MTase gene may result from attack of nucleases, for instance when the RM system invades a new cell. Its reassembly into a functional form, the order of motifs notwithstanding, may be strongly selected for, if the cognate ENase gene remains active and poses a threat to the host's chromosome. The "cut-and-paste" mechanism is proposed for β-δ permutation, which is non-circular and involves relocation of one segment of a gene. The circular β-ζ permutation may be explained both by gene duplication or shuffling of gene fragments. These two mechanisms are not mutually exclusive and probably both played a role in the evolution of permuted DNA MTases. |
format | Text |
id | pubmed-102321 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2002 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-1023212002-04-18 Sequence permutations in the molecular evolution of DNA methyltransferases Bujnicki, Janusz M BMC Evol Biol Research Article BACKGROUND: DNA methyltransferases (MTases), unlike MTases acting on other substrates, exhibit sequence permutation. Based on the sequential order of the cofactor-binding subdomain, the catalytic subdomain, and the target recognition domain (TRD), several classes of permutants have been proposed. The majority of known DNA MTases fall into the α, β, and γ classes. There is only one member of the ζ class known and no members of the δ and ε classes have been identified to date. Two mechanisms of permutation have been proposed: one involving gene duplication and in-frame fusion, and the other involving inter- and intragenic shuffling of gene segments. RESULTS: Two novel cases of sequence permutation in DNA MTases implicated in restriction-modification systems have been identified, which suggest that members of the δ and ζ classes (M.MwoI and M.TvoORF1413P, respectively) evolved from β-class MTases. This is the first identification of the δ-class MTase and the second known ζ-class MTase (the first ζ-class member among DNA:m(4)C and m(6)A-MTases). CONCLUSIONS: Fragmentation of a DNA MTase gene may result from attack of nucleases, for instance when the RM system invades a new cell. Its reassembly into a functional form, the order of motifs notwithstanding, may be strongly selected for, if the cognate ENase gene remains active and poses a threat to the host's chromosome. The "cut-and-paste" mechanism is proposed for β-δ permutation, which is non-circular and involves relocation of one segment of a gene. The circular β-ζ permutation may be explained both by gene duplication or shuffling of gene fragments. These two mechanisms are not mutually exclusive and probably both played a role in the evolution of permuted DNA MTases. BioMed Central 2002-03-12 /pmc/articles/PMC102321/ /pubmed/11914127 http://dx.doi.org/10.1186/1471-2148-2-3 Text en Copyright © 2002 Bujnicki; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. |
spellingShingle | Research Article Bujnicki, Janusz M Sequence permutations in the molecular evolution of DNA methyltransferases |
title | Sequence permutations in the molecular evolution of DNA methyltransferases |
title_full | Sequence permutations in the molecular evolution of DNA methyltransferases |
title_fullStr | Sequence permutations in the molecular evolution of DNA methyltransferases |
title_full_unstemmed | Sequence permutations in the molecular evolution of DNA methyltransferases |
title_short | Sequence permutations in the molecular evolution of DNA methyltransferases |
title_sort | sequence permutations in the molecular evolution of dna methyltransferases |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC102321/ https://www.ncbi.nlm.nih.gov/pubmed/11914127 http://dx.doi.org/10.1186/1471-2148-2-3 |
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