Back to Search
Start Over
Chlamydomonas chloroplasts can use short dispersed repeats and multiple pathways to repair a double-strand break in the genome.
- Source :
-
Plant Journal . Mar2008, Vol. 53 Issue 5, p842-853. 12p. 7 Diagrams, 2 Charts. - Publication Year :
- 2008
-
Abstract
- Certain group I introns insert into intronless DNA via an endonuclease that creates a double-strand break (DSB). There are two models for intron homing in phage: synthesis-dependent strand annealing (SDSA) and double-strand break repair (DSBR). The Cr.psbA4 intron homes efficiently from a plasmid into the chloroplast psbA gene in Chlamydomonas, but little is known about the mechanism. Analysis of co-transformants selected using a spectinomycin-resistant 16S gene (16Sspec) provided evidence for both pathways. We also examined the consequences of the donor DNA having only one-sided or no homology with the psbA gene. When there was no homology with the donor DNA, deletions of up to 5 kb involving direct repeats that flank the psbA gene were obtained. Remarkably, repeats as short as 15 bp were used for this repair, which is consistent with the single-strand annealing (SSA) pathway. When the donor had one-sided homology, the DSB in most co-transformants was repaired using two DNAs, the donor and the 16Sspec plasmid, which, coincidentally, contained a region that is repeated upstream of psbA. DSB repair using two separate DNAs provides further evidence for the SDSA pathway. These data show that the chloroplast can repair a DSB using short dispersed repeats located proximally, distally, or even on separate molecules relative to the DSB. They also provide a rationale for the extensive repertoire of repeated sequences in this genome. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CHLAMYDOMONAS
*CHLOROPLASTS
*DNA
*GENOMES
*PLASTIDS
Subjects
Details
- Language :
- English
- ISSN :
- 09607412
- Volume :
- 53
- Issue :
- 5
- Database :
- Academic Search Index
- Journal :
- Plant Journal
- Publication Type :
- Academic Journal
- Accession number :
- 30033449
- Full Text :
- https://doi.org/10.1111/j.1365-313X.2007.03376.x