Substoichiometric shifting in the plant mitochondrial genome is influenced by a gene homologous to MutS.
The plant mitochondrial genome is retained in a multipartite structure that arises by a process of repeat-mediated homologous recombination. Low-frequency ectopic recombination also occurs, often producing sequence chimeras, aberrant ORFs, and novel subgenomic DNA molecules. This genomic plasticity may distinguish the plant mitochondrion from mammalian and fungal types. In plants, relative copy number of recombination-derived subgenomic DNA molecules within mitochondria is controlled by nuclear genes, and a genomic shifting process can result in their differential copy number suppression to nearly undetectable levels. We have cloned a nuclear gene that regulates mitochondrial substoichiometric shifting in Arabidopsis. The CHM gene was shown to encode a protein related to the MutS protein of Escherichia coli that is involved in mismatch repair and DNA recombination. We postulate that the process of substoichiometric shifting in plants may be a consequence of ectopic recombination suppression or replication stalling at ectopic recombination sites to effect molecule-specific copy number modulation.
Plant Science Initiative, School of Biological Sciences and Beadle Center for Genetics Research, University of Nebraska, Lincoln, NE 68588-0660, USA.
Ricardo V
RV
Abdelnoor
Ryan
R
Yule
Annakaisa
A
Elo
Alan C
AC
Christensen
Gilbert
G
Meyer-Gauen
Sally A
SA
Mackenzie
D000251:Adenosine Triphosphatases / Q000235:genetics*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D001426:Bacterial Proteins; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins / Q000235:genetics*; D018745:Genome, Plant; D007700:Kinetics; D008928:Mitochondria / Q000235:genetics; D008969:Molecular Sequence Data; D051719:MutS DNA Mismatch-Binding Protein; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D017931:DNA Primers; D004272:DNA, Mitochondrial; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D000251:Adenosine Triphosphatases; C523213:MSH1 protein, Arabidopsis; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli