Mu-homologous sequences present in mitochondria?
--Carol Leja, Susan Gabay-Laughnan
and J. R. Laughnan
Several inverted and direct repeats are
known to be present in the mitochondrial genome of maize. Homologous repeats
may recombine with each other and, consequently, the DNA is reorganized.
Cytoplasmic reversion in cms-S lines of maize is associated with loss of
specific repeat sequences and/or reorganization of contiguous DNA sequences.
Two experiments were performed to determine the following: (1) whether
or not sequences homologous to the terminus of Mu, which may serve
as additional sites for recombination, are present in the mitochondrial
genome; (2) if present, do the termini indicate the presence of complete
elements that could be associated with apparent loss and reappearance of
mitochondrial DNA sequences, and (3) if present, do these elements account
for the highly unstable nature of a WF9-RD cytoplasmic revertant.
Mitochondrial DNA from WF9-RD sterile
and a corresponding cytoplasmic revertant (cyto-rev) was digested with
HindIII and EcoRI. The HindIII and EcoRI digests
were electrophoresed in a 1% agarose gel and blotted onto a nylon membrane.
The Southern blot was probed with a clone obtained from Vicki Chandler.
The clone, pDTE1, contains approximately 220 bp of the Mu terminus.
No homology to the Mu terminus was detected in the mitochondrial
Mitochondrial RNA from WF9-N x M82510,
WF9-RD sterile, WF9-RD cyto-rev, WF9-RD cyto-rev x M8257 (fertile) and
WF9-RD cyto-rev x M8258 (sterile) was electrophoresed in a 1.2% agarose
gel and blotted onto a nylon membrane. When the Northern blot was probed
with pDTE1, no hybridization signal was obtained.
Please Note: Notes submitted to the Maize Genetics Cooperation
Newsletter may be cited only with consent of the authors
to the MNL 64 On-Line Index
the Maize Newsletter Index
Return to the
Maize Genome Database Page