A horizontally acquired group II intron in the chloroplast psbA gene of a psychrophilic Chlamydomonas: in vitro self-splicing and genetic evidence for maturase activity.

ABSTRACT: The majority of known group II introns are from chloroplast genomes, yet the first self-splicing group II intron from a chloroplast gene was reported only recently, from the psbA gene of the euglenoid, Euglena myxocylindracea. Herein, we describe a large (2.6-kb) group II intron from the psbA gene (psbA1) of a psychrophilic Chlamydomonas sp. from Antarctica that self-splices accurately in vitro. Remarkably, this intron, which also encodes an ORF with putative reverse transcriptase, maturase, and endonuclease domains, is in the same location, and is related to the E. myxocylindracea intron, as well as to group IIB2 introns from cyanobacteria. In vitro self-splicing of Chs.psbA1 occurred via a lariat, and required Mg(2+) (>12 mM) and NH(4)(+). Self-splicing was improved by deleting most of t

SUBMITTER: Odom OW 

PROVIDER: S-EPMC1370600 | biostudies-literature | 2004 Jul

REPOSITORIES: biostudies-literature