Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes

We previously showed that the group II Lactococcus lactis Ll.LtrB intron could retrotranspose into ectopic locations on the genome of its native host. Two integration events, which had been mapped to unique sequences, were localized in the present study to separate copies of the six L.lactis 23S rRN...

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Main Authors:	Conlan, Lori H., Stanger, Matthew J., Ichiyanagi, Kenji, Belfort, Marlene
Format:	Online
Language:	English
Published:	Oxford University Press 2005
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1216334/

id	pubmed-1216334
recordtype	oai_dc
spelling	pubmed-12163342005-09-27 Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes Conlan, Lori H. Stanger, Matthew J. Ichiyanagi, Kenji Belfort, Marlene Article We previously showed that the group II Lactococcus lactis Ll.LtrB intron could retrotranspose into ectopic locations on the genome of its native host. Two integration events, which had been mapped to unique sequences, were localized in the present study to separate copies of the six L.lactis 23S rRNA genes, within operon B or D. Although further movement within the bacterial chromosome was undetectable, the retrotransposed introns were able to re-integrate into their original homing site provided on a plasmid. This finding indicates not only that retrotransposed group II introns retain mobility properties, but also that movement occurs back into sequence that is heterologous to the sequence of the chromosomal location. Sequence analysis of the retrotransposed introns and the secondary mobility events back to the homing site showed that the introns retain sequence integrity. These results are illuminating, since the reverse transcriptase (RT) of the intron-encoded protein, LtrA, has no known proofreading function, yet the mobility events have a low error rate. Enzymatic digests were used to monitor sequence changes from the wild-type intron. The results indicate that retromobility events have ∼10−5 misincorporations per nucleotide inserted. In contrast to the high RT error rates for retroviruses that must escape host defenses, the infrequent mutations of group II introns would ensure intron spread through retention of sequences essential for mobility. Oxford University Press 2005 2005-09-16 /pmc/articles/PMC1216334/ /pubmed/16170154 http://dx.doi.org/10.1093/nar/gki819 Text en © The Author 2005. Published by Oxford University Press. All rights reserved
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Conlan, Lori H. Stanger, Matthew J. Ichiyanagi, Kenji Belfort, Marlene
spellingShingle	Conlan, Lori H. Stanger, Matthew J. Ichiyanagi, Kenji Belfort, Marlene Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes
author_facet	Conlan, Lori H. Stanger, Matthew J. Ichiyanagi, Kenji Belfort, Marlene
author_sort	Conlan, Lori H.
title	Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes
title_short	Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes
title_full	Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes
title_fullStr	Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes
title_full_unstemmed	Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes
title_sort	localization, mobility and fidelity of retrotransposed group ii introns in rrna genes
description	We previously showed that the group II Lactococcus lactis Ll.LtrB intron could retrotranspose into ectopic locations on the genome of its native host. Two integration events, which had been mapped to unique sequences, were localized in the present study to separate copies of the six L.lactis 23S rRNA genes, within operon B or D. Although further movement within the bacterial chromosome was undetectable, the retrotransposed introns were able to re-integrate into their original homing site provided on a plasmid. This finding indicates not only that retrotransposed group II introns retain mobility properties, but also that movement occurs back into sequence that is heterologous to the sequence of the chromosomal location. Sequence analysis of the retrotransposed introns and the secondary mobility events back to the homing site showed that the introns retain sequence integrity. These results are illuminating, since the reverse transcriptase (RT) of the intron-encoded protein, LtrA, has no known proofreading function, yet the mobility events have a low error rate. Enzymatic digests were used to monitor sequence changes from the wild-type intron. The results indicate that retromobility events have ∼10−5 misincorporations per nucleotide inserted. In contrast to the high RT error rates for retroviruses that must escape host defenses, the infrequent mutations of group II introns would ensure intron spread through retention of sequences essential for mobility.
publisher	Oxford University Press
publishDate	2005
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1216334/
_version_	1611376783204024320

Localization, mobility and fidelity of retrotransposed Group II introns in rRNA genes

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