sears@msu.edu
Phone: (517) 355-0132
Home Department: Plant
Biology
Plant
Breeding and Genetics Program
Professor of Plant Biology; Ph.D, 1979, Duke University; NIH Postdoctoral Fellow, 1980-1983, University of Dusseldorf, President of the American Genetic Association, 1993 and Past President, 1994.
Chloroplasts and mitochondria provide the essential functions of photosynthesis and respiration to eukaryotic cells. Both of these organelles contain DNA that encodes proteins essential for energy production, but neither of them contains genes for proteins for the replication and repair of their own DNA. All of the genes required for replication, recombination and repair of organelle DNA reside in the nucleus. In some instances, those processes are very efficient: for example, in plants, the DNAs of both the chloroplasts and mitochondria appear to be resistant to mutation and hence their gene sequences are evolutionarily conserved. In contrast, animal mitochondrial DNA sequences have undergone extensive evolutionary change.
To determine if components of replication and repair are responsible for the high fidelity of chloroplast DNA maintenance, a genetic approach is being taken to isolate nuclear mutator alleles that increase the frequency of chloroplast gene mutation. Mutator target genes have been placed on the chloroplast DNA to act as reporters of specific mutation events. Other investigations in the Sears lab seek to manipulate the frequency of recombination of plant mitochondrial DNA, as a way of controlling aberrant DNA rearrangements that lead to debilitating developmental syndromes.Selected Publications
Chiu, W.-L. and B.B. Sears (1993) Plastome-genome interactions affect plastid transmission in Oenothera. Genetics. 133:989-997. Glick, R. and B.B. Sears (1994) Genetically-programmed chloroplast dedifferentiation as a consequence of plastome-genome incompatibility in Oenothera. Plant Physiol. 106:367-373.
Sears B.B., L.L. Stoike, W.L. Chiu (1996) Proliferation of direct repeats near the Oenothera chloroplast DNA origin of replication. Mol. Biol. Evol. 13:850-863.
Chang T.L., L.L. Stoike, D. Zarka, G. Schewe, W.L. Chiu, D.C. Jarrell, B.B. Sears (1996) Characterization of primary lesions caused by the plastome mutator of Oenothera. Current Genetics 30: 522-530.
Stoike, L. and B.B. Sears (1998) Plastome mutator induced alterations arise in Oenothera chloroplast DNA through template slippage. Genetics 149:347-353.
Hupfer, H., M. Swiatek, S. Hornung, R. G. Herrmann, R. M. Maier, W.-L. Chiu, and B.B. Sears. (2000) Complete nucleotide sequence of the Oenothera elata plastid chromosome, representing plastome I of the five distinguishable Euoenothera plastomes. Mol Gen Genet 263:581-585.
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