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Potential for alternative intron-exon pairings in group II intron RmInt1 from Sinorhizobium meliloti and its relatives.

ABSTRACT: Ribozyme constructs derived from group II intron RmInt1 of Sinorhizobium meliloti self-splice in vitro when incubated under permissive conditions, but exon ligation is unusually inefficient when the 5' exon is truncated close to the IBS2 intron-binding site. One plausible explanation for this observation is the presence of an alternative intron-exon pairing between an intron segment that overlaps with the EBS2 exon-binding site and a 5' exon site located just distal of IBS2 relative to the splice junction. Strikingly, the existence of this pairing is supported by comparative sequence analysis of introns related to RmInt1.

SUBMITTER: Costa M

PROVIDER: S-EPMC1383573 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature

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Potential for alternative intron-exon pairings in group II intron RmInt1 from Sinorhizobium meliloti and its relatives.

Costa María M Michel François F Toro Nicolás N

RNA (New York, N.Y.) 20060123 3

Ribozyme constructs derived from group II intron RmInt1 of Sinorhizobium meliloti self-splice in vitro when incubated under permissive conditions, but exon ligation is unusually inefficient when the 5' exon is truncated close to the IBS2 intron-binding site. One plausible explanation for this observation is the presence of an alternative intron-exon pairing between an intron segment that overlaps with the EBS2 exon-binding site and a 5' exon site located just distal of IBS2 relative to the splic ...[more]

PMID: 16431983

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Inactivation of group II intron RmInt1 in the Sinorhizobium meliloti genome.

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Splicing of the Sinorhizobium meliloti RmInt1 group II intron provides evidence of retroelement behavior.

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Use of the computer-retargeted group II intron RmInt1 of Sinorhizobium meliloti for gene targeting.

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Spread of the group II intron RmInt1 and its insertion sequence target sites in the plant endosymbiont Sinorhizobium meliloti.

Project description:RmInt1 is a mobile group II intron from Sinorhizobium meliloti that is exceptionally abundant in this bacterial species. We compared the presence of RmInt1 and two of its insertion sequence homing sites (ISRm2011-2 and ISRm10-2) in two phylogenetic clusters (I and II) identified by AFLP analysis in a collection of S. meliloti field isolates from Italy. Both clusters contained several copies of the ISRm2011-2 element, which is present at high copy number in almost all S. meliloti isolates. By contrast, isolates from cluster I harbored no copies of ISRm10-2 and only a truncated copy of RmInt1, despite the absence of constraints on intron mobility in this genetic background, whereas cluster II strains harbored several copies of this intron. The absence of ISRm10-2 from one of the strains of this cluster suggests that this element was acquired more recently than the other two elements. Furthermore, studies of insertional polymorphisms in cluster II strains revealed the acquisition of ISRm10-2 and subsequent retrohoming of RmInt1 to this homing site. These results highlight the role of intron homing sites (ISs) in facilitating intron dispersal and the dynamic and ongoing nature of the spread of the group II intron RmInt1 in S. meliloti.

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Complete Genome Sequence of the RmInt1 Group II Intronless Sinorhizobium meliloti Strain RMO17.

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Exon sequence requirements for excision in vivo of the bacterial group II intron RmInt1.

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