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. Published by Cold Spring Harbor Laboratory Press. Copyright © 2006 RNA Society.