PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of narLink to Publisher's site
 
Nucleic Acids Res. Apr 11, 1992; 20(7): 1747–1754.
PMCID: PMC312266
A maturase-encoding group IIA intron of yeast mitochondria self-splices in vitro.
S K Hebbar, S M Belcher, and P S Perlman
Department of Molecular Genetics, Ohio State University, Columbus 43210.
Abstract
Intron 1 of the coxI gene of yeast mitochondrial DNA (aI1) is a group IIA intron that encodes a maturase function required for its splicing in vivo. It is shown here to self-splice in vitro under some reaction conditions reported earlier to yield efficient self-splicing of group IIB introns of yeast mtDNA that do not encode maturase functions. Unlike the group IIB introns, aI1 is inactive in 10 mM Mg2+ (including spermidine) and requires much higher levels of Mg2+ and added salts (1M NH4Cl or KCl or 2M (NH4)2SO4) for ready detection of splicing activity. In KCl-stimulated reactions, splicing occurs with little normal branch formation; a post-splicing reaction of linear excised intron RNA that forms shorter lariat RNAs with branches at cryptic sites was evident in those samples. At low levels of added NH4Cl or KCl, the precursor RNA carries out the first reaction step but appears blocked in the splicing step. AI1 RNA is most reactive at 37-42 degrees C, as compared with 45 degrees C for the group IIB introns; and it lacks the KCl- or NH4Cl-dependent spliced-exon reopening reaction that is evident for the self-splicing group IIB introns of yeast mitochondria. Like the group IIB intron aI5 gamma, the domain 4 of aI1 can be largely deleted in cis, without blocking splicing; also, trans-splicing of half molecules interrupted in domain 4 occurs. This is the first report of a maturase-encoding intron of either group I or group II that self-splices in vitro.
Full text
Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.9M), or click on a page image below to browse page by page.
Images in this article
Articles from Nucleic Acids Research are provided here courtesy of
Oxford University Press