Organization and expression of the mitochondrial genome in cytoplasmic revertants ofcms-S maize

The loss of σ\sp\prime and $\psi\sp\prime$ termini of linear molecules was found to be a general characteristic of cytoplasmic reversion for all the nuclear-cytoplasmic genomic backgrounds examined in cms-S maize. Those cytoplasmic revertants that lose S1 and S2 lose σ\sp\prime and $\psi\sp\prime$ termini by recombination with σ and $\psi$ regions of the main mitochondrial genome to generate internal junction sequences of σ-σ\sp\prime, $\psi$-σ\sp\prime, σ-$\psi\sp\prime$, and $\psi$-$\psi\sp\prime$, thereby circularizing the mitochondrial genome. However, which internal junction sequences are generated appear to be influenced by the nuclear genotype. Cytoplasmic revertants that retain S1 and S2, namely those in the WF9 nuclear background, differ in the organization of their mitochondrial genome from those cytoplasmic revertants that lose S1 and S2. Although some data provide evidence for the loss of σ\sp\prime and $\psi\sp\prime$ termini by recombination with $\psi$ in these revertants, the continued presence of termini of linear molecules having σ/$\psi$ adjacent to a terminal S1/S2 and the presence of altered σ\sp\prime/$\psi\sp\prime$ termini suggest that circularization of the mitochondrial genome does not accompany cytoplasmic reversion in the WF9 nuclear background. Since S1 and S2 continue to be present after cytoplasmic reversion in the WF9 nuclear background, loss or mutation of σ\sp\prime and $\psi\sp\prime$ termini and of σ-R and $\psi$-R junctions may be a way to stabilize the organization of the mitochondrial genome as linear molecules. The 2 kb sequence common to σ\sp\prime and $\psi\sp\prime$ appears to result in the production of sterile-specific transcripts.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Leja, Carol Ann

Contributors dc:contributor

• Laughnan, John R.

• Biology, Molecular

Statement dc:rights

• Copyright 1991 Leja, Carol Ann

Language dc:language

eng

Identifier

AAI9136654
(UMI)AAI9136654

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20815